Is it too late to get into Rock Band?

So far this generation, I've let the whole 'band' genre of rythm games pass over me completely, mainly due to the insane UK prices at the time and the fact we never got the superiour Rock Band 2 instruments. However on a number of good sites now  The Beatles: Rock Band    is available for a very good price (around £90) and it is my intention to buy it along with Rock Band and Rock Band 2, but it got me thinking: is it too late? 
To understand where I am coming from hear this: I played and loved the original Guitar Hero. I was never that good at it, but I managed to complete it on medium and do about half of hard mode. Then I bought Guitar Hero 2 and you know what? I got bored with it half-way through. The appeal and novelty wore off and I was back to playing immersive rpgs, frantic fps' and good solid adventure games.  I know for a fact that a guitar only rythm game of that style no longer appeals to me so I will be buying the Rock Band games primarily for the drums - but would it be the same again? What is so different about the Rock Band experiance from the Guitar Hero experiance? Because if it is a similar experience with nothing noteworthy enough to make it feel different then I think I would rather save myself a bunch of money.  
I mean at the time back in old Gamespot days I remember Jeff, Ryan and Alex Navarro being pretty excited about Rock Band and that E3 (05 or 06 I think it was) where they had the whole crew playing at the end of the coverage was awesome. I know for a fact those guys played a hell of a lot of Guitar Hero before so for Rock Band to excite them there had to be something special about it but was it just hype?  
So I ask again: Is Rock Band still relevent? If you are a fan please convince me and if not then please try otherwise! 
I'm appealing to the community as (most) of GiantBomb is populated with level-headed dudes and well-informed opinion. Apologies in advance for this terrible, rambling mess of a first blog post!