I think that FBReader is a great software to read books on the Iliad because it supports many different types of file format. Maybe it is a lack of resources or other reasons, the update patches of fixed bugs are not immediate enough. But I think the FBReader is great overall!
Right now, the main problem for FBReader is that it lacks the publicity like Mobipocket. Most e-book users know Mobipocket but not a lot of e-book users know FBReader. Perhaps someone should port FBReader onto different hardware platforms, such as Neolux NUUT, Sony Reader, Amazon Kindle, and Bookeen's Cybook, to make it become a more well-known e-book software. The reader itself is great, but not a lot of people know it.