Classical music
The new software seems designed to frustrate those of us who listen to classical music.
The metadata on most classical music recordings is organised by composer, but the software is incapable of dealing with this in a sensible way. So in the "Albums" view, J.S. Bach appears under J, not under B. Same problem if you use the "Composer" view, particularly as a track identified as by "G.F. Handel" appears a long way away from one identified as just by "Handel" or even "Georg Friedrich Handel".
Improvements needed here, I think!
iPhone 6, iOS 8.4