Calculating max critical dmg on a Hero

so basicaly critical on a hero is pretty useless? Would it be better not to use my critical chance ring at all?

My crits are higher than my non-crits, so can't say crit is utterly useless for a Hero.
I prefer to wear my Cruel ring rather than my Crit ring, but that's based on pre-bb recommendations (which said Crit ring is only better when under SE). Haven't actually done or seen any math post-BB (or post Chaos).

I'm also curious as to whether a %crit line on my weapon is a significant increase in DPM, or I should try for %dmg, %att, or %str instead.