Well, my biased opinions are:
1) I use it on my site
ViperAlley.Com and we've sold over $1 million in merchandise (more than a dozen Vipers have been sold).
2) The links above probably help with choices - I never found any that integrated with Threads.
3) Yes, see ViperAlley.Com
4) I think so, much like PhotoPost (based on same code).
5) Bugging? Not sure what you mean? Buggy? The 1.8 release out now is stable and the current 2.0 beta 5 is fairly stable (and offers product bidding and user feedback).
6) Between myself and omegatron you have two very involved Threads people handling development and most of the support.
