After initially being annoyed with what are some pretty considerable bugs, I really really like reading on it (mine is an M90). Despite being right-handed, I have become accustomed to the left side page turns. I keep it in my lap while I read, or on a stand, so accidental page turns are a rare occurrence.
I'm just using mine for reading novels, so I cannot attest to any of the other features, which I suspect are not up to par. I also keep very few books on the device, as the sorting options leave a lot to be desired.