I got mine a month ago, and I’ve read 13 books on it so far. Its chief advantage is its size: the ability to carry it with me all the time and to pull it out whenever I have a free moment is great. (And also, although I have no evidence to support this, I think the smaller format helps me to read better, as I am able to focus on a small block of text rather than letting my eyes wander all over the page, as they are wont to do.) This little device may be the best $60 I’ve ever spent.
I loaded mine with cpr-vCodex. It has some useful features, and it gets updated almost daily. I find the “reading achievements” a bit gimmicky, but it’s otherwise a solid firmware option.