I couldn't resist the $179-shipped Fry's deal and got a jetBook. I have tried a few formats and am on Chapter 3 of a Tom Swift book in PDF format from Feedbooks. The PDF is a "custom" version with values that I found on the jetBook formum site. It is extremely readable. I also flashed it with the update as soon as I got it charged up.
My likes:
- The thing is georgous!
- The size. It is much smaller than a normal 6-inch reader.
- The screen. Mine is perfect. It has one of the issues described in another thread.
- A lot of people would say the instant page turns, but the "flashy" page turns of e-ink don't bother me.
- Books can be deleted directly in the jetBook.
- File folders for organizing books.
- PDF works well, especially when custom formatted.
- Mobi works well. Non-DRMed of course.
- I think RTF works OK with tweaking of the input file. The one I tried treated the entire book as one paragraph. I am pretty sure I can fix that in the original file, but haven't tried yet.
- Battery life compared to my Touch. I still read on it, but the battery life is so short that it's annoying. I expect to get a couple of days reading on the jetBook.
Things I don't like:
- No DRM support. Not a real big deal for me because I format shift most books anyway.
- Mixed results from epub books. I tried a couple that I generated via Calibre and they both stopped after the table of contents, which was 4 page in one book and 6 pages in the other. I've crossed epub off my list for reading on the jetBook.
- HTML support. It is not listed specs, but I did have one HTML book open. Others did not. This would be a welcome feature for me!
- Battery life. It is not in the same ballpark as an e-ink device!
- The book list is updated only when the SD card is inserted while the unit is on. I always turn my EZ Reader of to take out the SD card.
- The wife hasn't seen it yet and I'll pay dearly when she finds out I have yet another ebook reader!

My conclusions are that I like it. It is not as good as the current e-ink devices, but that is mostly from a software stand point. The jetBook with better software below the $200 could be a killer machine! The jetBook with better software at +-$200 would be a killer machine! By software, I mean formats that work and DRM; the general user interface with search, deleting files, etc. is fine. I have been doubtful about 5-inch readers, but now I firmly believe that they will do well in the marketplace! I believe that the magic price point for mass reader acceptance is $199. 5-inch readers could be that item!