Difficulty:

Just Right

Time Spent:

100 or More Hours

The Bottom Line:

"Best in series"

Guitar Hero World Tour, while might not be as challenging as GH3, it's still fun. It introduces drums, and mic (just like Rock Band).

Pros:

Drums and mic
Music Studio
Great Character Creator
Instrument Design (peripheral)
Online Game Modes
Great graphics

Cons:

Drums and guitar may have issues
Music Studio needs patience, to create good tracks
Online doesn't match that well
Career Mode is pretty much the same linear, except you get to choose gigs in order you want

The only reasons I give this an 8.5 is:

-0.5 for peripheral issues
-0.5 for online matching (different difficulty levels in Pro Face-Off)
-0.5 for other reasons like no "No-Fail" mode, not as much songs (DLC) as RB, and whatnot

If you are into the Guitar Hero series, I suggest you buy this, as it's a great game.
If you haven't yet played GH (maybe RB) this is a great game, and you should at least give it a try
If you've never played a music game, this is a great start, because (as opposed to GH3) is way less challenging, and you can make your way to expert faster.