Before I start, just know that I still only have guitars. I don't really have the money to shell out on drums and a mic, but I have a friend who has the full Rock and setup, so if they are compatible please let me know.
First of all, this is probably just me or my tv but hammered notes seem much more difficult to hit. Songs that look fairly easy now seem really difficult and I miss almost all the hammer notes. Even after calibrating lag, the timing this time around just seems much more precise than it was before and i'm having a difficult time adjusting. I also don't like the new purple notes slider thing because it puts the outdated guitars at a disadvantage. I played the newer guitar and it's way easier to tap than my guitar, so it feels a little unfair on some of the more difficult songs. Another strange thing is that I do much better when I have friends over playing bass. When I play by myself I sometimes get 85% notes on a song and then my friend comes over and I get 98%.... weird
The career feels pretty much the same, and I like the ability to choose gigs rather than make the game linear although I don't understand why I should pay for certain gigs. The selection of music is still pretty good, and overall not nearly as difficult as GH3. I'm about 90% done with the career, and I've hit a few difficult spots with B.Y.O.B. and Satch Boogie, but neither of these songs seems to be Dragonforce impossible so i'm confident that I'll be able to complete every song. I've only played a little bit with the music creator, and it seems like a neat idea. Making up something is easy enough, but translating things I already know on guitar into the game or trying to edit the song is a bit clunky with the guitar controller. The downloads work well though, and it will be interesting to see what people come up with that is not "let's tap random notes on the neck and make this really difficult" like many of the songs are.
The game looks a little different graphically, but it still feels very familiar. There are way more than 8 venues this time around and all of them look great. Many famous musicians including Jimi Hendrix make cameo appearances and really make the game more interesting. The character creator feels pretty standard, with several options for clothes, facial appearance, and the moves your character does during play. Brand name guitars are also no longer available, so every instrument you make is custom. The options are a little bit limited though, and sometimes I did wish that I could have a real Gibson as my guitar rather than something that I created that vaguely looks like one.
As for online play, I haven't actually gotten it to work. It's not my internet for a change because I played some online GH3 and COD4 and both worked just fine. I'm only left to believe that Neversoft's servers have died, but hopefully that will be fixed in the next few days.
That's it for Guitar Hero, I probably won't get any more games until after Christmas once I have more money but I probably won't be allowed to anyway
Enjoy the blockbuster season Gamespot,
~James

Butters782
P.S. I just read someone else's blog and they say that GH:WT and RB2 have compatible instruments.