Yes, it is great practice! But only if done right....
As a drummer who is getting back into it after years, I can totally say that from my experience the RockBand game has had a profound effect on my ability. But first, let me get a few of the usual arguments
out of the way.
1. It is no substitute for a competent teacher.
2. It does not teach the fundamentals of grip, posture, etc...
3. It does not chart the songs 100% true to form.
4. Yes, it does swap some colors (that really bugs me)
5. All double bass songs only have the right foot charted (according to Harmonix)
That being said, playing the game rekindled my love of drums. I stopped playing for years (life gets in the way) and it only took 10 minutes with this game and I literally ran out to buy an Xbox and the game. I then went and found a teacher also and started taking lessons again. How often do drummers who are not in bands (etc) get asked at a party or just asked "Hey, bring out your drums and play for us!" Usually, unless you are in a band, your wife/parents/friends don't really want to sit around and hear you bang. The game gives you the ability to jam, just like to a Hal Leonard book (which isn't 100% accurate either, lets face it, every drummer will play a song a tad different every time unless they are in a studio or doing session work). But, unlike play-along books, the game gives you incentive to keep practicing by rewarding you (if you don't think that works I don't know what to tell you).
Here is how I use the game: I take my drum instructor's lessons and apply them to the songs in the game after warming up with rudiments (etc). I try and incorporate rudiments into the fills, and use rudiments while playing (like a 2 stroke ruff, etc) where appropriate.
Can someone learn to play without an instructor just using a game? I highly doubt it, granted there are prodigies, but they are few and far between. If you are a good drummer and you find the game annoying because of the charting try this:
1. Turn on No Fail mode
2. Turn on Performance mode (this takes the rolling chart away).
3. Queue up a song or two
4. Play!!!! Who cares about the score!
You don't even have to use the game drum controller, or be hooked up to the game. The drum line will dissappear form the song, so, it will be just you playing what you want. Now, for $100 I challenge anyone to find me a book that contains such a diverse collection of drum music from basic to professional skill levels that has the drum tracks removed so you can play along!! There are over 500 songs, a Hal Leonard play along book will run you about $1 per song, if he charted every song in the game, the CD would cost you over $1,000 bucks! You get a ton of songs out of the gate for 10 times less than that, I think that is a fair deal. To many drummers get hung up on the scoring, who cares! Just use performance mode and no fail mode and play your acoustic or electronic kit alongside the game, you will know when you mess up and you can play any chart you want and stick any fill where you want. The drum track will not be heard in the song at all.