Well, they put up a warning page before every fic, as well as before every chapter and clicking through those can get tedious, especially when the chapters are short. Also, after you sign in the cookie that allows access to the fics runs out within a couple of hours, and you have to re-sign in frequently. That is frustrating as well. There is no way to view other comments made on a story the way FA and LJ have either (I think).

On the plus side, their search function works well, and you can search by pairing (even when pairing includes more than two characters), and they offer a bookmarking and alert system for registered members that lets you know when an author you've added to a favorite list has updated.