I'm trying Poweramp and so far I like it, I don't know if I'm not finding the option or is a new feature I think it should have, but this is a deal breaker for me as in the app right now if the album artist tag is missing it gets grouped under "unknown artist" instead of falling back to artist tag for correct sorting.
Let's say I have 3 albums of artist A, 2 of them don't have album artist tag but the 3 is a compilation with different artists per song (B C ... Artist) and album artist A.
Basically I can't access to all the songs of artist A in artist or album artist categories.
At least my previous music player uses the artist tag when album artist is empty in the album artist view.