I just switched to a Lumia 521 from an HD7 last week, as the latter phone was on the fritz. Anyway, been quite pleased with the Lumia (despite its shortcomings), but Holy Shit @ the clusterfuck that is the WP8 experience with Xbox music and the WP sync apps.
I'm a Zune HD user w/Zune Pass and the HD7 used to sync beautifully with my collection residing on my NAS and play all my Zune Pass music. Not so much anymore. Now I'm forced to use the barebones WP app to sync my music (sans my downloaded Zune Pass music and ratings info of course). And if I want to download new music using my "Xbox Music" pass, I have to use the dogshit Music app and download new versions of the same music I already have downloaded, but can't use. And then store it all locally, because it refuses to access my music share from my NAS (Despite the fact that the WP sync app talks to my Library/NAS share just fine).
How the fuck MS managed to drop the ball so spectacularly is completely beyond me. Same deal with other content they sell. I loath iTunes, but they manage to make access to all of your purchased content seamless on all your Apple hardware. MS looks completely incompetent by comparison.