I have one in .223. So I can't help with the caliber specific questions. I like the rifle. The action is small and a little more fiddly to operate than a standard medium action if you want to work it fast. It's fine for what you want to do with it though. Accuracy with the .223 is great. I dunno about the 7.62x39.
I always wanted one in 7.62x39. $450 seems a tad more than I'd pay, but maybe that's what they go for now.