Chinese are, IMO, one of the best AKs available. In fact other than an Arsenal SLR-107F (which I don't own) they are about the only AK that I'm interested in. I have two MAKs, one stamped and one milled, and a NHM-90 which is about the same as a stamped MAK-90. I paid $400 OTD for the NHM a few months ago. I'm still on the look out for another and $400 - 450 is my target price but I might go higher for a nice one. In fact when I bought the NHM I had seen it marked higher. When I went back to look at it I had $500 set as my upper limit of what I would pay for it. I ended up getting a better deal on it but yeah, I would have probably paid that for it because I had been looking for one for a little while when I found it. I don't personally buy guns without actually seeing them first so that limits me to what I can actually find in the shops and pawn shops I visit. This usually works to my advantage though since I've never found Gunbroker auction prices to be reasonable for my neck of the woods.
$500 is probably a bit on the high side, depending on your local market, but if it's nice and you want it I'd say buy it, pop in a G2 FCG and a couple other US parts and you'll never regret the decision.