I've owned a lot of head units over the last 10 years. This is, by far, the best one I've owned and it's one of the cheaper ones. If you don't need HD Radio, this is the new Pioneer head unit to get.
I've got two very minor complaints:
1. I wish I could navigate the XM stations like factory radios (ie list of stations, names, and songs currently being played at once).
2. The USB menu/navigation isn't attractive and can be a big PIA to navigate.