I was asked a few weeks ago to create a cheat sheet for eBooks so our staff could have something to reference and handout to the public. Luckily I had just read a very helpful post by Jason Griffey that really summed up a lot of issues with eBooks, file types and DRM. I asked in the comments if I could adapt the post and he said it was ok. So I did.
Since we will be getting Overdrive soon we put this on the other side.
Here is what some of us put together. Hope you find it useful.