Good thing I got it for PS3
I think that it is no substitute for GH3 though. I think GH3 has a much better system, not that Rock Band is bad, but I would still pick GH3 over it. If you think Rock Band is going to be the same as GH, then be prepared to be suprised. The basic concept is the same, but adds a totally new spin on it. The only thing I would say is the same is the fact that you strum when and what it tells you to strum.
Plus, think about it. How would the instruments connect to the wii. They cant use USB like the PS3 version, meaning you may very well have to have 4 wiimotes to play all of the instruments together, and even if it is built in to the instruments, then the price will probaly be higher, since there was no wireless technology required with the drums for PS3