Choice Band/Specs
I think we need Item discussion! (Maybe so I can expand this into an Item Analysis Guide Later)
So yeah let's talk about items!
Particularly Choice Band/Specs since I decided to write them first.
Mechanics
The concept behind Choice Items are simple - If you make a choice, you are expected to stick with it, just like a man. Never looking back to "what ifs", the Pokemon puts all it's effort into this one move - and is stuck with it until you switch out, in exchange for boosted power or speed. While Choice Band raises your Pokemon's Attack stat by 1.5x, Choice Specs raises your Pokemon's Special Attack stat by 1.5x.
If a Choice Item user uses Sleep Talk, it works as it should once, but it fails the second time onward until the Pokemon switches out. Also, if a Pokemon uses the move "U-Turn" and the player switches to a Choice Item using Pokemon with U-Turn, then Choiced Pokemon is stuck using U-Turn.
If a Choice Item user uses Trick, they are free to select a new move the next turn.
So why should you use it? I mean, being stuck with one move doesn't sound too happy. It's asking for your opponent come in and force you out, or maybe even set up on you as it comes in on something you resist in. Is this really worth it?
Of course it is! Here are the benefits to using the items Choice Band/Choice Specs.
Choice Band/Specs may give you that extra power needed to KO something.
Take for example, Choice Specs Salamence. Choice Specs Salamence is one of the biggest threats in the metagame, with it's ability to kill nearly everything with the right moves. This is because the extra 15.4% boost it gets over the Life Orb variants give it just enough power to 2HKO certain Pokemon with Draco Meteor. The same goes for Gengar, who, with Choice Specs have the ability to 2HKO Blissey with Focus Blast.
Furthermore, Choice Band/Specs may give you that surprise no one would expect. Not many people would expect Choice Band Jirachi, or Choice Band Dusknoir. With the boosted power, you may notice that the usual "counters" may be 2HKOd, or OHKOd. This of course, assumes that the Pokemon you are using has a diverse enough move pool, and a high enough Base Power to be a legitimate threat.
It is useful for revenge killing
Many fast Pokemon have very little attack (Dugtrio, Aerodactyl), or have attacks that have very little base power (Weavile). Choice Band/Specs help fix this problem, allowing these Pokemon to serve as highly effective Revenge Killers - switching in after a Pokemon has fainted and avenging their fallen team member.
No need for setup
Because it does not take up a turn, unlike moves such as Sword Dance, Choice Band/Specs allows the Pokemon to start smacking things hard the turn right after it switches in.
Choice Band makes Pursuit and U-Turn more dangerous
Choice Band in particular gives that extra power to moves such as Pursuit and U-Turn, making them even more deadly against players who enjoy switching. Pokemon such as Weavile and Tyrannitar are common Choice Banders who carry Pursuit.
Choice Band/Specs forces Opponents to take risks, and allows you to take advantage of this
Meet Choice Band Heracross. With Guts, Base 125 Attack, and two STAB Moves with Base 120 Power, combined with the 1.5x boost from Choice Band, not much can stand in it's way. It's only problem - it's not exactly fast, and many Pokemon outspeed it.
The beauty of Heracross becomes apparent when it switches in on something like Blissey, Cresselia, Tyrannitar, etc. Many of these Pokemon will be threatened by the notion that Heracross is in front of their faces. It can easily OHKO them. Thus, the best move they have is to switch out, to try switch into a resist or a immunity. Yet, the Heracross player can predict this, and attempt to smack the Gengar or Gyarados switch in as hard as possible with Stone Edge.
The Heracross player then is in an interesting position and can play mindgames. It can predict the opponent will play it safe and switch out, and thus it's in their best interest to smack the opponent as hard as it can. And even if the Heracross player plays it safe - it still smacks the switch in hard - meaning that the "counter" cannot keep switching into Heracross forever.
It makes great use for Trick
Things such as Rotom and Alakazam are very good Choice Specs users for their ability to Trick them into Walls, crippling them very hard. Even if they never use the move Trick, their boosted Special Attack can make them rather hard to counter.
Of course, Choice Band/Specs does have it's flaws.
You are locked onto that move
This means that if your opponent predicts correctly, they can potential start setting up their strategy. Using Choice Band/Specs will naturally grant your opponent turns to set up.
It does not allow you to set up
Many choice item users also have access to things such as Calm Mind, Bulk Up, Sword Dance, and Nasty Plot. These moves, in the long run, might have caused more damage than using Choice Band/Specs.
Sleep Talk fails after its first use
As awesome as the prospect of Sleep Talk Choice Band/Spec user may be, Sleep Talk can only be used once when you use a Choice Item - forcing it to fail if you use it again.
You are vulnerable to Wobbuffet, Dugtrio, Magnezone, and Pursuit
Wobbuffet and Dugtrio can switch in and essentially score a free KO against Choice users, since the Choice users would be locked onto a given move. Magnezone can also do the same against Steel Pokemon.
Furthermore, Psychic and Ghost Pokemon are in trouble when they're locked into a move, and Pokemon such as Weavile, Tyrannitar, Heracross, etc, switch in (assuming of course they resist the move the Choice User is locked on), as it means that the Choice user is essentially dead or deathly crippled. The case is the same for really fragile pokemon such as Porygon Z.
In conclusion, Choice items add another level to the game that did not exist in RBY/GSC, and to an extent, Ru/Sa. It rewards prediction, and it breaks stall thus creating a speedier metagame. When making a team, or when playing competitively, it's definitely an item to consider.
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Updated.
I think we need Item discussion! (Maybe so I can expand this into an Item Analysis Guide Later)
So yeah let's talk about items!
Particularly Choice Band/Specs since I decided to write them first.
Mechanics
The concept behind Choice Items are simple - If you make a choice, you are expected to stick with it, just like a man. Never looking back to "what ifs", the Pokemon puts all it's effort into this one move - and is stuck with it until you switch out, in exchange for boosted power or speed. While Choice Band raises your Pokemon's Attack stat by 1.5x, Choice Specs raises your Pokemon's Special Attack stat by 1.5x.
If a Choice Item user uses Sleep Talk, it works as it should once, but it fails the second time onward until the Pokemon switches out. Also, if a Pokemon uses the move "U-Turn" and the player switches to a Choice Item using Pokemon with U-Turn, then Choiced Pokemon is stuck using U-Turn.
If a Choice Item user uses Trick, they are free to select a new move the next turn.
So why should you use it? I mean, being stuck with one move doesn't sound too happy. It's asking for your opponent come in and force you out, or maybe even set up on you as it comes in on something you resist in. Is this really worth it?
Of course it is! Here are the benefits to using the items Choice Band/Choice Specs.
Choice Band/Specs may give you that extra power needed to KO something.
Take for example, Choice Specs Salamence. Choice Specs Salamence is one of the biggest threats in the metagame, with it's ability to kill nearly everything with the right moves. This is because the extra 15.4% boost it gets over the Life Orb variants give it just enough power to 2HKO certain Pokemon with Draco Meteor. The same goes for Gengar, who, with Choice Specs have the ability to 2HKO Blissey with Focus Blast.
Furthermore, Choice Band/Specs may give you that surprise no one would expect. Not many people would expect Choice Band Jirachi, or Choice Band Dusknoir. With the boosted power, you may notice that the usual "counters" may be 2HKOd, or OHKOd. This of course, assumes that the Pokemon you are using has a diverse enough move pool, and a high enough Base Power to be a legitimate threat.
It is useful for revenge killing
Many fast Pokemon have very little attack (Dugtrio, Aerodactyl), or have attacks that have very little base power (Weavile). Choice Band/Specs help fix this problem, allowing these Pokemon to serve as highly effective Revenge Killers - switching in after a Pokemon has fainted and avenging their fallen team member.
No need for setup
Because it does not take up a turn, unlike moves such as Sword Dance, Choice Band/Specs allows the Pokemon to start smacking things hard the turn right after it switches in.
Choice Band makes Pursuit and U-Turn more dangerous
Choice Band in particular gives that extra power to moves such as Pursuit and U-Turn, making them even more deadly against players who enjoy switching. Pokemon such as Weavile and Tyrannitar are common Choice Banders who carry Pursuit.
Choice Band/Specs forces Opponents to take risks, and allows you to take advantage of this
Meet Choice Band Heracross. With Guts, Base 125 Attack, and two STAB Moves with Base 120 Power, combined with the 1.5x boost from Choice Band, not much can stand in it's way. It's only problem - it's not exactly fast, and many Pokemon outspeed it.
The beauty of Heracross becomes apparent when it switches in on something like Blissey, Cresselia, Tyrannitar, etc. Many of these Pokemon will be threatened by the notion that Heracross is in front of their faces. It can easily OHKO them. Thus, the best move they have is to switch out, to try switch into a resist or a immunity. Yet, the Heracross player can predict this, and attempt to smack the Gengar or Gyarados switch in as hard as possible with Stone Edge.
The Heracross player then is in an interesting position and can play mindgames. It can predict the opponent will play it safe and switch out, and thus it's in their best interest to smack the opponent as hard as it can. And even if the Heracross player plays it safe - it still smacks the switch in hard - meaning that the "counter" cannot keep switching into Heracross forever.
It makes great use for Trick
Things such as Rotom and Alakazam are very good Choice Specs users for their ability to Trick them into Walls, crippling them very hard. Even if they never use the move Trick, their boosted Special Attack can make them rather hard to counter.
Of course, Choice Band/Specs does have it's flaws.
You are locked onto that move
This means that if your opponent predicts correctly, they can potential start setting up their strategy. Using Choice Band/Specs will naturally grant your opponent turns to set up.
It does not allow you to set up
Many choice item users also have access to things such as Calm Mind, Bulk Up, Sword Dance, and Nasty Plot. These moves, in the long run, might have caused more damage than using Choice Band/Specs.
Sleep Talk fails after its first use
As awesome as the prospect of Sleep Talk Choice Band/Spec user may be, Sleep Talk can only be used once when you use a Choice Item - forcing it to fail if you use it again.
You are vulnerable to Wobbuffet, Dugtrio, Magnezone, and Pursuit
Wobbuffet and Dugtrio can switch in and essentially score a free KO against Choice users, since the Choice users would be locked onto a given move. Magnezone can also do the same against Steel Pokemon.
Furthermore, Psychic and Ghost Pokemon are in trouble when they're locked into a move, and Pokemon such as Weavile, Tyrannitar, Heracross, etc, switch in (assuming of course they resist the move the Choice User is locked on), as it means that the Choice user is essentially dead or deathly crippled. The case is the same for really fragile pokemon such as Porygon Z.
In conclusion, Choice items add another level to the game that did not exist in RBY/GSC, and to an extent, Ru/Sa. It rewards prediction, and it breaks stall thus creating a speedier metagame. When making a team, or when playing competitively, it's definitely an item to consider.
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Updated.
