GHWT as a game itself just annoys me for so many reasons. The timing window for hammer-ons/pull-offs still seems too wide, so I'll miss a note, but end up hitting it anyways, and that'll just fuck me up further.
Then there are just a lot of little things that annoyed me. Playing on hard mode guitar, the charts still vary insanely from "stupid easy" to "why are there this many fucking notes for this song?" None of it felt very consistent to me.
Also the way the game does vocals isn't nearly as good as Rock Band, and that's another aspect of these games that I love, so having it be so tacked on in GHWT was a disappointment.
Also, Rock Band 2 has a far better career mode, going through all of Band World Tour by yourself, instead of the boring "climb the ladder, okay you're done" thing that Guitar Hero still does if you play by yourself.
Rock Band also has the better character creator. You get a lot of sliders for your rocker in Guitar Hero, but very few clothing options, and no matter what you do your character still ends up looking like some horrible freak of nature.
I just don't get how GHWT is still not good considering Neversoft could have just been looking at Rock Band for some time now. I find it amazing that with all that time both companies had between sequels, Neversoft still ended up making a game that on a technical and UI level, still isn't as good as Rock Band 1, much less Rock Band 2.