I couldn't help but try the game out a bit though, so I played a few songs (I always start on medium to get a feel for things) and let me tell you - tons of fun.
I mean, I like the game in general, but the Metallica songs are fun to play and songs that are non-Metallica are awesome - such as Bob Segar's "Turn the Page" (not surprising since Metallica covered the song a few years back) and Alice in Chain's "No Excuses."
Other featured artists include Lynyrd Skynyrd, Thin Lizzy, Foo Fighters, Queen, Suicidal Tendencies, Social Distortion and more.
What's great is that they aren't all really well-known songs.
So if you like Guitar Hero and you like hard rock/metal/punk/hard core music (genre-izing music can be so difficult sometimes ...), check this out!