I bought it because it was comparatively dirt cheap and was hackable. I was delighted at how nice it actually was to use. I figured it'd be crappy in some ways, but, you know, at least it was cheap. To the contrary, it's perfectly fine and does a great job at letting me flip through ebooks.

What it's not good at it showing any kind of diagrams, because even if the software was decent, it's a relatively tiny screen. I haven't even bothered trying to view a PDF on it and don't know if that's supported. For epubs I've uploaded to it through Calibre, it's utterly adequate.