I just played through the first 3 chapters on drums. Very neat. It's not quite as video-gamey as previous rock band and guitar hero games - really focused on the music, (That said so far its a ton easier than the other music games that have come out in the last two years.)
Although there has been GH Aerosmith (which I did play all the way through) and GH Metallica (Which I toyed around with but didn't finish - way frickin' hard) This is just different. I guess there's just so much history there, so much to work with as far as all the different visuals and multi-media that have accompanied the Beatles music over the years... and not to mention - pretty decent and realistic physical renditions of the guys that aren't uncanny and scary like the polygonal Aerosmith and Metallica of the GH variety - that I'd be perfectly content to just watch someone else play it and just tap my feet to the music.
Would be a good game to have around on say, Christmas or Thanksgiving or one of those other multi-generational, bizarro get togethers.