I am one of the very early users of Pi, I have been using this device for more than 10 months. If you are reading normal text based PDF files, its good. Though its gets stuck some times. The funny part if every time its stuck I round around to find a sharp device to reboot it, I don't understand the logic of having a small reboot button for the device which needs so frequent resets.
If you try to open a PDF with images and sizes more than 40 MB then you will have lot of problem like the device gets rebooted in a never ending loop or its stuck at the boot screen. Every time I see this issue the only solution suggested by support is to install the firmware. I have seen this issue two times in last 10 months. To my understanding if there is a problem with the file or file is too big to open then it should exit gracefully and should not hamper users from reading any other book till be re-installs the firmware.
Too bad, I guess some basic stuff they should have checked before they ship the device.
Hope they resolved these issues in the latest pi2.
