I got into the Harmonix games during my injury downtime. I've competed in some Harmonix tournaments during the summer and played casually during parties. Let's just say the game has occupied a massive amount of my time and I figured I should write a review about Guitar Hero series and Rock Band.
The Rock band video game costs a whopping $160 and comes with a CD, a set of drums, a microphone, and a remote control guitar made by the Fender company that was actually modeled to look like an actual Fender Stratocaster. The amazing thing about this game is that it has an extra five frets near the bottom, so it replicates a real guitar compared to the Gibson Les Paul Guitar Hero 3 model. It also makes it easier to do the hammer-ons and slides as well.
The drums are by far the most fun to play, because the coordination and timing is almost like playing drums in real life. The realism is sort of shot because there are no cymbals or bass drum. All in all, it's just fun using your forearms to beat on these pads. Playing the drums is probably the main reason why I bought this game myself.
The only element of the game that is actually "real" is the microphone. The Multiplayer mode allows you to karaoke through an entire playlist of songs, so it's fun for singers and karaoke enthusiasts. The problem is that most kids that play these games wouldn't know more than half of the catalog unless they are into hard rock and alternative. If you bought Rock Band for this intended purpose, get Singstar instead.
For the people that are trying to learn how to play real guitar, the Harmonix gaming series will help strengthen your finger flexibility and scales. But in the end, Guitar Hero is not a substitute for playing a real guitar.