What costumes have the best passives

[Wafflehead]

I have some of the new Stylish costumes but I'm not as thrilled with some of their passives like I was Toon and Glass. 

What costumes do you LB2?

[NevarMaor]

S1 costumes I have only LB2'ed toon Azlar since that is the only one I have most of the costumes for (missing glass and now stylish, used to have the full set once ). I personally like the glass passive better, reflect rather than just resist. Eventually I will get around to LB2'ing C1 Leonidas and C2 Domitia for titans (both currently LB1).

Most non-S1 costumes that I have are just variations on the original and I don't bother LB'ing them at all. I have LB2'ed Lord Loki for the debuff copy.

[JoshuaK]

Season 5 costumes, especially as the passives cross over to the base!

[Ginger]

I like the S1 and S5 so far. 

[Gargon]

If you are only talking about S1 heroes then I think I generally like the toon passive the best, it has the widest range of effects and the highest % to trigger.
Glass is basically a downgrade from toon, which is why they had to add the extra ability (bypass for hitters and reflect for healers) afterwards to make up for the worse passive. in some situations that makes the deal good enough, but I wouldn´t bother with it in most cases.
The stylish passive is an interesting option for certain niches, most notably vegetables, as they can counter the fiends (which toon cannot) as well as wither effects (which have become a thing again on the buffed killer bot minions). Also the option to turn dot into healing can be powerful.

But the most powerful costume passive in the game right now is probably the Musketeer passive, which has entered the meta and is in some parts even format defining.