The only way to actually analyze this is to throw out the specific songs that are on each game because debating those is simply an opinion. I would say Guitar Hero 3 is the best. This is because for hammer-ons, they glow much more than the other games. Thus, in Guitar Hero 1 and 2 it's much harder to determine which notes are hammer-ons. Also, the fact that by the time Guitar Hero 3 came out, the franchise had become extremely popular. Due to this, a majority of bands were willing to release master tracks for the game, rather than the creators being forced to find covers. Thus, the quality of the sound is better because it is what the artists originally intended.
