Well, i dont usually write reviews but because i took a long time to decide wich game to purchase, this or Rock Band 2 i decieded to give my 2 cents about this.
First of all, the first thing i read about both games was that Rock Band had a cooler setlist. Well for me, it doesn't. I took the time to review all the musics in each game and i came up with a list... this list told me how many songs i enjoyed and knew in each game. Suprisingly in GW i know/like about 50 musics in 84 so thats about 60% of the songs, as in RB2 i liked/knew 40 musics, 45%. Did the list because online, since the cool musics I KNOW are spread along the setlist it seems to give a wrong impression, so my advise is take the time to ear the musics and write them in a txt and compare directly.
2nd part. As for gameplay, Guitar Hero is great in single player. All the comotion about "ho, they get songs toghether in concertes that dont mix" well imo, dnt care!! I played the entire game, and it gives you that kind of feeling that you're a garage band rocking your way up to the stars, and as such you play different kinds of music, but not to the point to bother you. In the Band Play it lacks the option that RB has to "Save" a member that as f"#@d up, and "died". And thats the only point against it, since there were times when a newbie friend came to play and failed 5 times in a row, we could've continued and save him/her. This was very contested online in forums and likes, because its hard bla bla bla bla, well if its so dificult (like the tool concert, schism especially, was to me) just put the difficulty to begginer. Yes its harakiri of your pride, but it comes a time you just want to pass that song, and begginer gives you the opportunity to pass that song and you always can go back and finish it again.
3rd graphics. Online they say RB has a more realistic figures, and the graphics are better, well, in my opinion its kind of pointless unless you're watching instead of playing because when you're playing you don't look to the avatars, you're just to concentrated in the guitar/drums highway to get the notes.
4th THe instruments, one of the main things thatr made me go GW instead of RB was the drums and the guitar. The drums, after 2 months of constant play, have no problem what-so-ever, and they take a bit of abuse, since there are some musics that u can't help to go balistic on it. True that you can buy madcatz cymbals to RB, but its just not the same, since the cymbals have the same colors of the drums, so not so convincing. I heard tha RB2 instruments are good, but since in EU i dont seem to find them on sale i cant compared them and must stick to RB instruments 1 (shame).
5th The other thing i would enjoy to have in GW would be that the game told me the difficulty for each instrument seperatly for each song, something that apparently RB does.
In conclusion, i prefered the GW: World Tour because of the setlist (wich i must say, its a personal opinion)and instruments. It was a great investment, its a party rocker, love to do early dinners with GW as a desert with my friends. There isn't anyone that was indiferent to it, everyoone eager to try it (boys go crazy with drums, girls just love it all, but especially getting the mic and singing along with one or two friends). Its not very dificult, especially if you do the first part of tutorials, you'll be rocking in easy setting hitting 85% upwards, if u dont just put it on begginer untill you get the rythm.
I have no aspiration to be a guitarist, i know i suck in real life, and GW gives me the oportunity to make all those monkey buisness holding a guitar in your hand. The learning curve for easy its about 1 or 2 hours, for medium it took a longer time about 10 or 12 hour since i didnt want to go medium untill i got the more difficult songs above 95%. Hard, i dont know, since i didnt get there yet, still perfecting on medium.
Hope i was helpfull.
Cheers for reading :)