Overall, I've been really impressed. My only complaints are towards the software. So far I've noticed:
1)Maybe I'm insane or just missing it, but it looks like the spiffy new software is missing an ID3 tag editor. If that's the case, I'm flabbergasted since that's such an important feature to a music ripper/player.
2)Also, it now seems to not want to tag art onto the artist folders of my subscription music (but it will tag the individual album folders).
3)Finally, it's much more sensitive about files being moved. In the old version I could move a folder and it'd know where to find the music still. I tossed all my Zune Pass music in the subscription folder (which it now defaults to) and it couldn't find the files, leaving me with having to empty my library and drag and drop those folders back onto it again. It seems the old WMP-based version was a bit more robust in that regard.
Other than that...wow. The client software is gorgeous and the store is so much faster. The same can be said for the firmware. There used to be pauses backing out of menus on the device which are now gone. The album art rendering when skimming through the lists is also much quicker.
All in all it feels like new life was breathed into my old black 30.
PS: It's GREAT to finally have built-in podcast support. I've been using the "suggest a podcast" link like crazy.