I'm going to re-post and post my thoughts about the Pokémon I used in my japanese White 2 run. I'll get my english Black 2 today, so I'll get 6 more Pokémon out of that.
Ducklett: Mid Tier
Availability: It's available relatively early, after the fourth gym and is a 100% encounter.
Stats: As a Ducklett, this Pokémon survives on its high HP stats to hit back, though not as hard as many other Water-types. However, when it evolves, it becomes much different. Swanna is really fast and has good mixed offensive stats to take control. Unfortunately, Swanna is really frail and won't survive many powerful attacks.
Typing: Water is always a good offensive typing; however, when paired with a Flying-typing, Water's defensive capabilities are really hampered. Its STAB have perfect coverage, as the only Pokémon that resist both Water and Flying is Empoleon.
Movepool: Man does this Pokémon get good moves. Ducklett has Bubblebeam when you catch it, and shortly after that it learns both Air Slash and Roost. Not long after the fifth gym, you get hold onto Surf, which means Swanna will deal heavy damage to the weak opposition. Swanna also learns Brave Bird at a decent level to give it mixed properties; it can also learn Ice Beam to deal more damage to certain Pokémon, but it comes late.
Major Battles: Ducklett shined against Clay to some degree. It can easily handle Krokorok and Sandslash, though Excadrill can definately be a hard nut to crack. Skyla is not dangerous at all either, as Swanna will hit all of her Pokémon for good damage. Drayden and Marlon are two huge roadblocks. Their Pokémon are not hit super effectively by its moves which coupled with their bulk means that Swanna will have trouble KOing them. Swanna frailty will also be apparent here. For the same reason, Swanna doesn't shine against most ofthe E4 Pokémon either.
Additional Comments: Swanna is a mixed bag. It is fast and hits kinda hard, while it can go mixed. Though it is frail and can't take many powerful hits from its opponent, espacially late-game. But with perfect coverage throughout the game, and powerful moves on top of that, it's still pretty great.