The GUI is great. Also the integrated scanning for audio content.
But the sound has some strange hiccups on my N800 (specifically at the sudden changes in sound volume when playing with a lot of dynamic range). Later I installed Kagu, which has a less attractive user interface but the sound is good.

Only Media player that detected all of my media. Still not all of the video's (all avi) were screenshot, but it found everything and I can play everthing.