I hate how the advertisement on the opening screen is like 4x bigger than your game icon, and how the social and video tabs are in front of the games tab. But I like how your XBLA games are displayed with boxarts now.
Cloud saves are awesome though. No more swapping hard drives, no need to buy a memory card, I can just put all of my J360 saves into the cloud and be ready to go. Best thing about the new dash. Until my saves are mysteriously deleted and I lose 100s of replays.