I'd like a reader that would just display plain text and simple HTML, nothing fancy. So I could download various reading material off the web and read it at breakfast, or on the train, or...

I would never buy one that uses DRM or a proprietary file format (this claims to have the latter), as it probably wouldn't be all that useful. The bottom line is that if it's designed to sell me books I'm not interested, but if it's designed to let me read the books and papers and articles I already have on my computer, then I'm listening.