Has anyone ever had an eBook taken away from them?
I don't think I've had an individual book taken away by an operating publisher (but it might have happened without me noticing it), but they do republish books now and then with slightly different content, and other people have reported losing books.
The bigger issue is keeping the servers up. When Fictionwise went under/got bought/whatever it was they kept the servers up for a while. Most of the Fictionwise books I bought were DRM free, a few were protected, but I managed to download them in a format that I could decrypt. It wasn't the best format, a lot of markup got left behind, but I did keep the content. Shortly thereafter they gave us a "free" account at a competitor (or maybe the company that bought them) and "let" us keep the books that publisher had in their catalog, which didn't include any of mine. I have seen reports of other "mergers" that resulted in content loss.
Same thing that happened to people who bought music from publishers who used Microsoft's "Plays for Sure" scheme. Microsoft shut down the servers and people lost access to their music.
The other challenge is - we do not have a light in our bedroom. I know most of you are thinking, "so buy a lamp." We tried that and it kept getting unplugged. So, I NEED something that has a built in light if I'm going to read after dark. Reading in the living room is pretty much a non-option for me. There are too many distractions.
I use a regular Android tablet. I do have a few books from work that require me to use an iPad, and it's a really nice screen, but it's too much hassle to copy files to the iPad so I can read them there without going through proprietary shenanigans.