Suggestions: Don't dumb down the gameplay. But often times a terrific song would be ruined by a horrible cover of it. I feel that the set list of GHII was a little better than this one.
The major thing done with this game in the series is getting the master tracks for many of the hits found in the game. Sound: The most important part of a Guitar Hero game. Although I miss some of the old characters, (Pandora!!) I must say that the new models look very nice. When I look back at GHII, it just looks bland. Graphics: The graphics got a nice overhaul since GHII.
New songs aren't released nearly as quickly as Rock Band, but GH offers free downloads much more often. DLC is a little pricey, but is a very welcome addition. I would also have loved to have a good lobby system with several people in a match and a spectator mode, similar to the system in Street Fighter. I would have liked to be able to play an unlimited amount of songs in a private match with my friends. I don't really mind it because it doesn't take anything away from the core gameplay. It's not a mode that I frequently play, and I'm sure there are plenty who love it.
In my opinion, the addition of guitar battles was unnecessary. GHIII brought two additions to the game: guitar battles and online play. At first I thought this was a bad thing, but when I played the actual game, I realized that the difficulty of the actual songs made up for it. Specifically, there is a bigger window in which you can strum or hammer a note without missing it. The first thing that I noticed was that the gameplay was noticeably easier. My first experience playing the game was with the demo that was released several weeks before its launch date. So you can imagine my excitement for GHIII. I played GHII until I could 5* ALMOST every song on expert. Gameplay: My Guitar Hero addiction began with GHII. If you're new to the series, this isn't a bad game to start with. Overall if you're a fan of the Guitar Hero series this is a must have. The graphics are as colorful and vibrant as they should be. The addition of online play was necessary. The gameplay has been slightly simplified with more forgiving timing. The setlist has been much improved with the addition of master tracks. Overall: It's the same amazing Guitar Hero gameplay.