I only have Linux machines at my disposal and I have a PocketBook. The device is nice, but the store is truly abysmal. Often there is some adobe based DRM on books I want to buy and I never got it to work with my ereader.
I just gave up and pirate them now, unless there is a DRM free version (authors like Ruther Bregman and Cory Doctorow provide them.)
It used to be quite easy to strip DRM from kindle books, with my old kindle keybaord, so in the past I always bought a lot of ebooks from Amazon. But now I can't get them on my device anymore. A true shame, the Amazon ebook store really has all the books.
This whole situation p**es me off enough to not feel bad about pirating.