There are some things I like about the new music app but plenty that I don't. The hamburger menu is an ugly and very clunky way to do a UI compared to the panoramic UI of XBM. I don't like the new style jump list and the app is missing band bios, similar artists and album reviews. The similar artists thing in XBM has put me onto several really good bands I didn't know about before, it's not something I will give up willingly.
It's not all bad, though, the new Now Playing screen is excellent and it is way better at finding album artwork. Still, overall it isn't as good as Zune was on WP7 so it's a little disappointing. Hopefully it will get some of the missing features. I also think that both N7 Player and Audiotica are better players.