Pros: Line out, Capacity, Rockbox (and therefore native .FLAC support), Ruler-flat frequency response, battery.
It's exactly what it says it is. I've tried some pretty incredibly expensive DAPs - Honestly, in my opinion, a lot of them just add colouration, or EQ, or look pretty. Some of them do perform well, but fall short in many areas.
If you just want your music files to reproduced exactly as they were mastered, with a line-out to pipe your music into any amplification you might require.. Get this device.
Pinpoint accurate, to points that are far beyond the limits of human hearing. Adds no colouration, and Rockbox has fantastic EQ and crossfeed options if you want, not to mention .FLAC playback.
A lot of people will hate on this device because it is mass-produced, and loved by the general population.. If you're thinking about an expensive portable DAP, just be wary of what you're buying.
When you spend hundreds more, on a DAP that has less battery, capacity, playback options or general functionality, ask yourself - why not spend the money on headphones that will make a significant difference?