-to hit and defense question - fire/rad

It actually is the same: debuffing an enemy's tohit by 5% (or any other amount) is exactly equivalent to +5% defense (or any other amount), against attacks from that enemy.

But there's a couple wrinkles that can cause enemies to actually be debuffed by an amount other than what your debuff applies. The first is the Purple Patch, which will make your powers less effective against foes above your level. The second is Archvillain debuff resistance, which resists tohit debuffs.

So, your -30% tohit is just as good as +30% defense, against a non-AV enemy your own level. On the other end of the scale, a level 54 AV (with you at 50) would reduce your debuffs to .48 effectiveness (-14.4%), and then resist 87% of that, so your 30% debuff would only reduce their tohit by 1.87%.

Tohit debuff enhancements are schedule B, so you can get to ~56% enhancement before ED becomes severe. Slotting both powers to the ED cap would give you ~47% of tohit debuffs total, which will floor the hit chance of +0 non-AV enemies, even with no defense at all, but you'll need more debuffs or some defense if you want to be softcapped against higher foes.

A notable difference:

Debuffing an enemy's To Hit by 5% is the equivalent of giving yourself and every one of your allies an additional 5% defense to the debuffed enemy only.


(Luckily, RI is an AoE, so it affects multiple enemies.)

Good point. A defense buff works against attacks from any enemy, but only for the character(s) buffed. A tohit debuff works against attacks only from the debuffed enemy/enemies, but benefits any character being attacked.