So far, I've only had two complaints with the JetBook:
The minor complaint is that the screen, while still non-glare, still has more glare than the Kindle. Just requires a little more fidgeting to get the right angle for reading.
The major complaint I have is the font rendering engine. I can put up with the font selection, but the rendering is horrible. It reminds me of some of the very EARLY incarnations of the FreeType engine on Linux. Straight lines are okay, but diagonal strokes and curves all look like they have a some sort of static or digital fuzz which just makes the letters look nasty ...