Gratz, this is the second thread about it in a very short time

I actually discoverd this quite a while ago when I was trying to break the cauldron back when it first came out. It's very strong! But here's a strange thing - the actual benefit comes from never being really able to get the 100% out of your potions which overheal allows for, and having a naturally large health pool. However, there's another way to make bigger health potions count.
Take a halfling monk with maxed out resists, a RBS for slow strike, and a few other debuffs, or even a halfling berserker on the right map, with a Naga Cauldron. I can't say for sure any of them are in fact stronger than a priest, but I'm not sure they're weaker, either.