On the SBF forum I opened a
poll months ago, right now we have 11 owners out of 31 that had problems, mainly with the power switch and the USB port.
(Remember to adjust the rate to account for the observation bias that is typical of online "support" forums, where people with problems are more likely to post than "satisfied" users.)
Moreover, if you visit Bookeen's facebook/twitter/blog pages, you will read other customers lamenting the same problems.