Well I do. But I don't like these games. Specifically it is because of their use of incredibly popular rock songs. Now I'm not one of those kids who's music taste is the least popular bands he can find. I like the songs themselves, but they make for some awful note charts.
The games are OK as long as you're playing guitar or singing, but a lot of these songs have very repetitive bass or drums. For this reason, GH/RB are the only music games that can actually make me want to take a nap. This isn't meant to be funny, playing the same few notes for the duration of a 4 minute song can be very underwhelming.
I especially don't like Rock Band's drums. I don't like the symmetry and the pedal would be easier if it had it's own column instead of being one big line. Speaking of columns, I don't like the way the notes scroll (at you).
I think it's been quite clear that I'm leading up to something with this post, and I am. Guitar Freaks and Drummania are much better. They're made by Konami and are part of the Bemani series so you know they're good. The reason you haven't heard of them is because they're Japan only. I've played them both though, and they're great. I'll explain one at a time.
Guitar Freaks would look bad to someone who was used to Guitar Hero. This is because it only has three frets. They go a long way, however, because Konami tends to make the best note charts for music games (not counting DDR). I've played the games, and I much prefer Guitar Freaks' charts to Guitar Hero's. Anther thing I like about it, and this applies to GF and DM, is that it pays attention to timing. GH and RB, from what I've gathered, care more about whether or not you hit the note than how well you timed it. GFDM focuses on the actual timing of the note, so your score wouldn't be as good if you hit them a little early or late.
Drummania is more significant in this argument. Instead of having four drum pads, it has five (technically speaking it's three drums and two cymbals). There's also a pedal. The new drums that Guitar Hero is going to have will have the same number to my understanding, but DM's drums are more laid out (google for a picture of them). Drummania's charts make it a shining example of how fun a music game should be. This is because instead of going with popular songs that mostly have pretty repetitive drums, Konami uses music with more intricate drumming. A lot of songs are written specifically for the game by artists affiliated with Konami and as a result, are made to be easy to make great charts for. You can watch videos of people playing this and get a good idea of how great it is, but I can tell you from watching videos and having played it that videos won't do any justice to how fun DM actually is.
The best part of GFDM is that with the "V" series of games, Guitar Freaks and Drummania were put into the same game in a Rock Bandish fashion (except this was before Rock Band). This is why I've been referring to them as GFDM. I've done sessions at a friend's house before (he has an electric drum set that is setup to be used as a DM controller) and they're great.
I first played GFDM before trying Rock Band or Guitar Hero, which is why I never liked either of them very much. I can see why people would like them having not played GFDM, and plenty like them all, but I'm quite partial to GFDM.