Maybe not a game for guitarists.
Your review is the same response to the game that I've heard from most of my guitar playing friends: it's nothing like playing a real guitar, so they don't like it. I don't really understand the complaint - as mentioned above, you wouldn't play a driving sim expecting to have to replace your broken rear tail light or be cut off by some idiot in a Mercedes, would you?
I don't play guitar, but do enjoy this game immensely. I'm fairly good with several other instruments, and once you get used to the game and the controller it's more or less like playing sheet music along with a band or orchestra. As with playing in an ensemble you have to stay in time, playing the right notes as your cues come up. The actual fingering isn't a transferable skill, but the improved sense of rhythm and good feel for music that comes with many years of group performance can be put to good use. The game is far easier to pick up than a real instrument, a good laugh to play with friends, and you get to pretend to be a rock star. I could hardly ask for more.
And MattBryant - there might not be a BFG, but there are several end of stage bosses including Slash and the devil (Lou).