I'm a player who has been with Guitar Hero and Harmonix since the beginning, and plays everything on expert on guitar and I have to say that those who outright claim that Rock Band has no good guitar are downright crazy. There are some amazingly cool and challenging solos in Rock Band when you get to the top tiers, such as "Flirtin' With Disaster", "Train Kept 'A Rollin'", and especially "Green Grass and High Tides", which may be the greatest guitar rhythm song ever, in my opinion.

The timing window for hitting notes in Rock Band is much more precise than in GH:III. You have to actually hit the note right on, not any of this "just get close" stuff. I went back and played Guitar Hero III the other day at my friend's house, as I don't own it myself, and played "Cult of Personality" and hit some 90-something percent of the solo. I found it so easy to get the notes after previously needing such exact timing on "Green Grass...". So, in short, Rock Band does have fun, challenging guitar, just in the right way, and not just the "lets throw craploads of notes on the screen at once" way.

The charting in GH:III is terrible, 3 note chords are used everywhere, and it doesn't even make sense or feel right. They make simple songs seem so challenging to play. Plus, the drums in Rock Band are amazingly fun, and it's a great multi-person game.

So, that's my take on the matter.