What format are you reading the books in? Some don't accuratly handle page numbers for quitting and returning to the same page. From what I've seen so far, FB2 handles pages fine at the expense of a slightly longer opening time for the book.
I did have reboot issues with a couple of versions of the BeBook/Jinke firmware although I can't remember which specific versions. I'm currently using the latest openinkpot snapshot. The previous snapshot ran fine for the last month (on a single charge no less and still 25% battery left), installed the latest snapshot last night, hopefully it'll be just as stable
There's instructions on how to load openinkpot on their website, it's pretty simple. Look at the sticky threads in the openinkpot forum, there's a direct link to the latest firmware snapshot and install/user guides. The process is basically, download the 64 or 512 meg version depending on which device you have, extract the zip and copy the v3update.bin to a SD card that is either just been formatted or is under 1GB in size. Turn on the device whilst holding down the + key, follow the onscreen prompts and job done.
Only problem I've noticed with the recent OI firmware is that FBReader doesn't want to open fb2.zip books anymore, but coolreader works fine.
I'd advise against using the live version of OI, I had no end of reboot/freeze problems with it. It's much simpler to just flash your device with the latest OI and if you don't like it, you just flash back to one of the Jinke/BeBook firmwares. If anything goes wrong during the flashing (as happened to me last night), you stick something in the reboot hole, hold down + and try the flash again.