The little bit I played last night was kinda disapointing... To start the guitar wouldn't work out of the box, no matter what we tried it would never connect wirelessly. The interface and menus are little funky but probably could get used to them. I just don't think that I would buy it the way it stands, I would rather have my couple hundred songs with rockband 1 & 2, and save my money
The drums seem nice and an improvement over rockband drums, but you basically have to use the control pad if you need to navigate in the menus.
The guitar is really nice, too bad it wouldn't work... I'm glad that red octane and EA are getting along and you can use the guitars between each game, I will probably pickup one of the guitar hero guitars for rockband