How's your learning progress been?
I'd say at the moment I'm a solid beginner. I can read simple sheet music and can play (although not particularly smoothly) three chord songs. I want something to help me get to the next level. I was looking into piano lessons but they're like $70 a week so stuff that. Synthesia looks good for that.
Those keyboards are really expensive :S
I did create a thread on GAF about it some time ago but it appears to be gone. The program itself is a great tool for learning while taking some of the laborious tasks away (e.g. sheet music, although there is an option to turn that on).
I am still what I classs as a beginner and I haven't used it much lately due to other interruptions. The only thing it was lacking in was fingering techniques, however they do have a guide now to recommend what fingers you should be using for what notes, also there are a number of midis people have created for practicing scales which will help a lot.
You can definitely learn to play with this program/game but if you're using a keyboard it will still take a bit of practice to transition to a piano (due to the action difference most of them have).
I can't see the website, but it sounds like it could be quite handy. Would the Rock Band keyboard be decent enough for it?
If you can use the keyboard on a PC it will be fine for a starter keyboard, probably check the forums to see if anyone has got it working.