Let's take a look at say the top 30 OU threats (random number).
Code:
#1. Scizor
#2. Tyranitar
#3. Salamence
#4. Heatran
#5. Latias
- Rotom-a
#6. Gyarados
#7. Jirachi
#8. Metagross
#9. Gengar
#10. Swampert
#11. Lucario
#12. Infernape
#13. Rotom-h
#14. Starmie
#15. Blissey
#16. Gliscor
#17. Azelf
#18. Magnezone
#19. Skarmory
#20. Vaporeon
#21. Suicune
#22. Breloom
#23. Machamp
#24. Flygon
#25. Celebi
#26. Zapdos
#27. Dragonite
#28. Jolteon
#29. Forretress
#30. Kingdra
Now we can remove threats Trace deals with effectively. I will also use asterisks (*) to show which abilities will not directly help CAP10 deal with the threat but can still be beneficial.
Code:
#1. Scizor
#2. Tyranitar
#5. Latias*
- Rotom-a*
#7. Jirachi*
#8. Metagross
#9. Gengar*
#10. Swampert*
#11. Lucario
#12. Infernape
#13. Rotom-h*
#14. Starmie*
#16. Gliscor
#17. Azelf*
#19. Skarmory
#21. Suicune
#22. Breloom
#23. Machamp
#25. Celebi*
#26. Zapdos
#27. Dragonite
#29. Forretress
Seeing this, the main threats that need to be dealt with are
Scizor, Tyranitar, Metagross, Lucario, Infernape, Gliscor, Suicune, Breloom, Machamp, Zapdos, and Dragonite. I don't consider many defensive threats to be threats CAP10 needs to counter. However I will go over why I did not mention the ones here.
I'm going to compare
Status Immunity to
Magic Guard as unbias as I can for each threat.
Scizor - Status immunity does nothing. Scizor doesn't carry any status.
Magic Guard helps against CB sets who continually switch out with U-Turn by ignoring EH/SS damage.
Tyranitar - Status immunity again doesn't do anything as Tyranitar doesn't carry status.
Magic Guard ignores Tyranitar's constant SS damage which helps to stop it from stalling CAP10 down. It also gives a slight advantage against Choice sets who will switch out repeatedly.
Metagross - Neither ability helps much. The only
mentionables are
Magic Guard can run Life Orb to potentially score a much easier 2HKO while being defensive enough to take a few hits if it can avoid switching into Earthquake. The rare Trick variant can also be countered with Flame Orb. These are very weak points but are still points.
Lucario - Neither ability helps much again. Slight mentionables are LO variants of
Magic Guard can simply outrun and OHKO without having to resort to a Choice item.
Infernape - Neither helps much here either. U-Turning around will hinder CAP10 as well as constant switches and the EH immunity provided by
Magic Guard is appreciated but nothing beyond that.
Gliscor - Gliscor's Taunt/Toxic set is handled excellently by
both abilities.
Magic Guard does this ever so slightly better since Gliscor is commonly run on SS teams and the immunity always helps.
Suicune -
Neither ability helps beyond ignoring Toxic Spikes.
Breloom -
Status immunity handles this better than Magic Guard
in one aspect since it doesn't have to waste an item with Toxic/Flame Orb and doesn't have to switch in once before hand to handle Spore.
Magic Guard deals with Leech Seed far easier on the other hand
(not using Deck Knight's example of status immunity because I just plain find it silly to make a non-Magic Guard Magic Guard while Rising Dusk's is more stable).
Machamp -
Status immunity handles Champ much better since it is immune to confusion. Though Magic Guard prevents confusion recoil, it will still waste a turn.
Zapdos - Toxic sits at 13.8% and Thunder Wave at 7.8%.
Status immunity handles it better in terms of Thunder Wave though it's lack of use is rather
ignorable. Toxic doesn't affect
Magic Guard either and Thunder Wave is only a problem to Toxic Orb sets if it hasn't switched in prior to. Magic Guard also has no issue with Roar which is run 13.4% of the time. I'd give the advantage to Magic Guard.
Dragonite - Dragonite carries status on extremely rare cases, both Thunder Wave and Toxic are under Other at 5.2%. 252/252/4 Hp/Def/Sp.A
Magic Guard with Life Orb can survive any attack Dragonite throws CAP10's way, even +1 LO Adamant Earthquake, and OHKO back with Ice Beam as long as SR is down (or a turn of LO recoil in the case of Offensive DDNite).
Status Immunity - 1 (Machamp) || Magic Guard - 8 || Undecided - 2 (Breloom, Suicune)
So in short there is
no reason to run a custom Status Immunity ability instead of Magic Guard. It's only true advantage is Machamp and even then Magic Guard is hindered only a bit less.
Now at this point I want to
make sure Trace isn't being completely outclassed by Magic Guard. I'll go back over the threats Trace can be used effectively against and compare them to Magic Guard.
Salamence - Salamence is very tricky, as
both Trace and Magic Guard can survive its most powerful attack aimed at CAP10, +1 LO Earthquake, reliably. However
Trace gives a better switch in to MixMence, since it can take Outrage and Earthquake slightly better thanks to Tracing Intimidate. Magic Guard, of course, ignores SR damage which is nice but most would use Trace to handle Salamence securely.
Heatran - Seeing as how Toxic is in the Other section of usage,
Trace does a remarkably better job. Taking 0% from a potentially Flash Fire boosted Fire Blast greatly offsets the EH immunity Magic Guard provides.
Gyarados -
Trace, hands down, takes Gyarados. The only thing mentionable for Magic Guard is the rare Roar Gyarados who will still get Intimidated twice by Trace.
Blissey - Very torn. Trace has the advantage of being able to take Thunder Wave switching in for the first time and then switch out and lose paralysis. Magic Guard can stall Blissey down even when it fires off Toxic. However, I feel Trace wins this battle. Blissey is key set up bait for most sweepers, and knowing which status it carries immediately without any repercussions will be very helpful. Since Blissey in most cases would end up stalling CAP10 down a ridiculous amount anyways, switching out and losing Toxic is just as useful. This argument can go both ways, but my personal opinion is
Trace.
Magnezone - There is no question using
Trace to copy Magnet Pull will be incredibly more useful than Magic Guard.
Vaporeon - Another very difficult choice. This is about as undecided as Blissey: Surf is turned into HP with Trace while Toxic is rendered useles from Magic Guard. I once again have to go into personal territory and say
Trace is more useful. Though both abilities do not fear Vaporeon, a STAB resisted Surf is more powerful than unSTAB'd HP-Electric. Surf is on 88.8% of sets while Toxic is on 22.8%. This is debatable but I believe Trace comes out on top.
Flygon - Flygon seems tough until you realize
Trace immunizes it's main way to deal damage to CAP10. Magic Guard is nice against constant U-Turning thanks to EH immunity, but if a set is made to counter Flygon it shouldn't have any problem switching into Choice Band Earthquake.
Jolteon -
Trace is 100% the victor since it turns any of Jolteon's main offensive options against it and Thunder Wave (10% of all sets) also grants Trace extra staying power.
Kingdra - Toxic isn't mentionable on any Kingdra and the advantage of being able to
Trace Kingdra's Swift Swim (or even Sniper) will be vital to bringing down this threat.
Trace - 9 || Magic Guard - 0 || Debatable - 2 (Vaporeon, Blissey)
I do not see any other ability which covers all of Trace's weak spots while not contesting the threats handled more effectively than
Magic Guard. Those who consider Magic Guard + LO to be offensive, one look at Infernape, Zapdos, Salamence, Starmie, or Latias will show you it is
extremely outclassed as an LO sweeper. The immunity to passive damage is great, but the terrible offenses don't help it sweep, it helps it tank. And even the CAP10 has to pool all its resources into offenses in order to be a threat and thus has an immensely difficult time taking hits from any set up sweeper, any tank that can hit SE and take a hit (there are many), and any wall.
Who would use CAP10 as a sweeper when you have infinitely better options at hand? Clefable is only considered a sweeper because of Belly Drum and an incredibly powerful recoil STAB attack. I need not remind you
CAP10 has neither of these and thus cannot be considered a sweeper in comparison. Oh yeah, and
NO ONE RUNS LIFE ORB ON CLEFABLE ANYWAYS. Smart players in UU know Clefable's defensive options outclass its offensive.
However I do see there is potential to counter much more with this ability.
Poison Heal is a very viable substitute and those who do not support Magic Guard due to its immunity to passive damage should turn to Poison Heal next.