I believe the visitor messages is the feedback he's referring to. If so then the fact that it's in there as visitor messages and not in a "feedback" section would be one reason why it is hard to find.
One easy feedback area for member services is simply the comments section below the add, as can be seen here: Honing By Lynn, Founder of SRP - Straight Razor Place Classifieds
I used Lynn's ad since he's the head honemeister so it just seemed right to use someone who is undisputedly good at this.
The official feedback and rating area can only be gotten to by clicking on the member-in-question's name while in the classsifieds section: Member Profile - Straight Razor Place Classifieds
If you go to their profile from anywhere else in the site you cannot reach this section (as far as I can find). Now, it seems pretty obvious to me that those saying the feedback system is hard to find/use are right because even Lynn's actual feedback is completely blank and instead people use his ad's comments or visitor messages to give feedback. We have an entire rating system here that is being largely ignored because most people don't know about it or can't find it.
I don't have a really helpful opinion on any of this, I'm way too new for that, but I saw that people were referring to the feedback system and thought this might help a little.
EDIT: Looking at a few other honers' profiles it seems that some have had their feedback systems used, but not all, so it looks like some people really don't know about this system. Perhaps a simple guide for this linked in the classifieds section as a sticky somehow (if there isn't already one that I just missed)?