Despite the current featureset and the reasonable price-tag, the current feedback system is kind of a deal breaker for me.
It seems anyone can leave feedback for anyone else at any time, and that you can only leave one feedback rating per person (no matter how many transactions you perform).
Any plans on improving this?
You may want to check out
http://www.phpbb-auction.com/.
They seem to have a better feedback system, which perhaps you can incorporate into your product.