I have my first impression of the site.  It is quite simple and easy to move through.
(1) I expect the homepage will change in the future to be a bit more interactive and engaging because i hit the home button ALL the time on webpages. But it serves it purpose right now.

(2) The user tab is nice. I like how it is just my name in the corner. I like how it provides me with my account info right off the bat. All BTC values, USD conversion, and rating. I'm sure "feedback" will be clickable and allow me to see all corresponding users, comments, and ratings broken down in a useful format.
 -With regards to the "invite friends" tab, I would make it an "Affiliates" tab. "Invite friends" can nest under that, as well as, various other links like facebook or twitter, or advertisement code and rates. etc.
-I really appreciate transaction history having its own space. Some very respected and mature BTC sites either have this important info hidden or dont provide it at all. Like BTCJam.com.
-My final critique today has to do with the lack of some sort of order book. I do like the search capability of specifying what amount I am willing to facilitate, but I wish I could view ALL open orders at once.