It suffers a lot of the same problems that iTunes did...
Features dont fit in the UI so they all get "grafted" in.
If your on a playlist that isnt yours, there is not a good way to figure out the year the song is from (is it new, is this from the 60's ... ). Then its 3 clicks to get back to your current play list.
They need to figure out what the next 5 years of feature are and build a UI redesign that will support that + more.