I'll repost my impressions from another thread:
Here are my observations--
Improvements:
-TXT bug fixed
-Remnants of the 'y' in 'By Author' gone
-Definitely faster throughout
Things that still aren't working as expected:
-Text from books doesn't take the entire screen. In non-PDF files, there's a progress bar on the right-side of the screen. It doesn't extend to the bottom of the screen and neither does the text!
-Justification settings still aren't sticking for me. Quickest way to change it to full justify is to type 6, 4, 2, in an eBook. Menus are still a bit slow, even though the overall speed is faster as far as I can tell.
Does anyone know whether jetBook uses FBReader?
Bottomline: It seems like some of the bugs from 33c have been ironed out and this version would be worth using if you are still on 30i. ePUB support is much better.