I was most interested in their solution for this. I like that you can give specific ratings and leave a comment like on many e-commerce sites. They might want to throw in a "reply" type of thing if someone leaves a reputation comment that is untrue so the merchant can give his side. The detailed moderator rating is good too, it's good that it separates between winners and losers.
Yes, a follow up comment is always helpful. Many negatives can be false or untrue or based on minor disagreements that the buyer left in frustration. I think the feedback system here should have a similar option so others can voice their side of the situation.