More in performance than core/memory speed. If after performance I'd go with the 5850. If looking for performance/cost, I'd probably (O I did) go with the 5770.
Almost half the cost, Lower power consumption. (That's a good indication that it may not beat the 5850. - But not sure the increase is worth it) - That's an individual question.
That's exactly what I'm debating right now. Can someone try to elaborate on this issue? Is it really worth the money to get a 5850 over the 5770?