One benefit of using Rain is it works best with the pet cc build (burning dogs + big stinker = many freeze/stun/chill/knockback procs - and the frogs on top seal the deal on a particularly troublesome elite). I've had success keeping pets alive long enough to refresh cooldowns by using a combination of +armor, +all resistances, and lockdowns applied with rain of toads and acid rain (the pools appear to hit a LOT). Playing with the melees (monks and barbs) also helps get pets over the inferno hump.