I really like it, unique concept. Here are some of the benefits.
1) No fees, no adverts, no commission
2) Auto-bidding, system allows you to place a maximum budget and will bid for you when you are gone
3) Student section, allows university students to trade within their universities. So if you are looking for a coursebook for cheap or to sell this is the place.
4) I like how each user gets a unique profile which is rich in information and multimedia
5) Easy to use seller template, which can accommodate videos.
6) Clean design, a lot of attention to detail.
7) Most important, communication is transparent, you can comment on listings and have a fun time with other bidders or ask more questions to the seller. This is a big plus.