GameTrailers.com gives it an 85, and writes:
Guitar Hero III abides to the "If it ain’t broke, don’t fix it" approach by sticking to the tried-and-true formula established in the first game and honed in the second.
In the very next excerpt, also an 85, Electronic Gaming Monthly writes:
The "ain’t broke, don’t fix" approach is evident.
As is the "short deadline, tired critic" approach.