I'm about two thirds of the way through the hard level. Some days I'm better than others but I'm getting better at it all the time. Won't help me with most of what I'd expect to see at Jamfest now (though Spanish Castle Magic and Crossroads, maybe Godzilla could be close). I'm having a hell of a time with Guitar Hero. It's loads of fun, and has a very playable learning curve. It's actually kind of seductive...when you start getting good you're almost left feeling that you could pick up a real guitar and play it on that too. The music's good too if you're into guitar rock.
There's a conversion out there where you can plug these controllers into USB and use it as a MIDI controller. That could be fun.
I have some other ideas for Jamfest next time. Will post on that when I have it more fleshed out. It might work out, but it might not. Will see.