Longbox Digital is now in open beta so go download it. So far it's extremely stable and I am loving the integrated Comic Book Resources news feed. There are Public Domain .cbr files suitable for testing available at Golden Age Comics.
Updated feedback
1. No easy folder or file management, yes drag and drop support is there, but the option to just add a folder should be also.
2. No keymapping option, as of now there is no way to designate preferred keys like page up/page down for in file navigation.
3. The most glaring omission is that there is no true full screen mode. There is no option to hide the user interface for truly immersive reading.
Pre-Beta Screencast
http://www.vimeo.com/6153232+info here
http://longboxdigital.com
