This module went into large refactoring last year, and seeing the API change everyday was annoying, to say the least. But the result worth the wait. The new OO API is way more consistent and usable than the previous one. It also tries to keep up-to-date with features that are added to mpd. The test suite that fakes a mpd daemon is also a strong point.
My mpd scripts are now about three times shorter than the old ones. Definitely a sign of a well-done job.