I've just filed a bug about the incorrect display of AlbumArtist in the now playing screen:
https://bugs.maemo.org/show_bug.cgi?id=8817

Generally, if your files are correctly tagged with AlbumArtist (i find Musicbrainz picard to be the best way of doing this), maemo handles them pretty well. There's just the problem with the now playing screen, and it would also be nice if there was an option to browse by both "album artist" and "artist" seperately, instead of the current way which only allows "album artist".