Well, it is very easy to load books on to - acts like an external drive. Perhaps check calibre here:
http://calibre-ebook.com/
At the moment calibre has full support for the SONY PRS 300/500/505/600/700, Cybook Gen 3/Opus, Amazon Kindle 1/2/DX, Netronix EB600, Ectaco Jetbook, BeBook/BeBook...