The sound quality is also excellent, IMO. From what I can tell, it's using some driver called vaclcskd.sys (I know this because if you run the Breakaway DSP (Winamp plugin usually) and AIMP 2 at the same, you'll get a blue screen of death with this driver as the culprit. Fun times.) instead of DirectSound. I think this vaclcskd.sys driver is some kind of proprietary kernel driver.
Either way, I'm not sure if the driver is doing some kind of transform on the audio, but I think it sounds different from foobar2000 in a good way (I wish I had ReplayGain available so I could level match, etc.). It almost seems like the AIMP 2 output driver has a better hold on the processing. The audio just "feels" tighter, more accurate. It's like an instantly recognizable PRaT improvement more than anything else to me. Could be all placebo, but I don't think so.
The audio library/playlist setup is decent enough. Playlists sit on the top of the playlist window as tabs. The audio library is a separate window from the main app and works well enough. AIMP 2 reads tags blazingly fast.
AIMP 2 supports Winamp DSP plugins and some general Winamp plugins, so all is not lost if you switch from Winamp. Output plugins aren't supported AFAIK.
Additionally, the built-in equalizer is full of features (you probably don't need ), and should satisfy most basic tinkering desires (iZotope Ozone or a similar DSP should take care of the rest). The tempo adjuster can be fun for those who are bored.
I haven't touched this yet, but as well as I can see, AIMP 2 also supports online radio station recording and audio conversion to FLAC/MP3/OGG/MusePack/FAAC/WMA/WAV with what looks like CD ripping capabilities (EAC is still going to be better, but hey).
I'll be playing around more with AIMP 2 over the weekend at home. I'm hoping a few others will as well. It's a great little player so far, and I'm hoping I can flesh out a few more nice tweaks and tricks to really make it a contender for music playback on a regular basis.