Right up my alley !
I have a Roland GR-50 (the rack mount jobby), and I love it.
I'm a poor, poor keyboard player (2/4 finger, kinda like typing this message), and with the guitar synth, I can do virtually anything (within my technical ability) I want. I can input MIDI data using the guitar as a controller, I can record synth audio directly to disk or tape, it's stereo, I can create my own funky patches, I can control other synths, it's limitless.
And yes, it is a toy, but what a fun one. And freakin' addictive.
Although, you really want a good controller -
the GK-2A works, but unless it is permanently mounted, it doesn't track as well as it could. I've got
a Godin LGX-SA that is the cat's meow - well worth EVERY penny...
But that's just my opinion, yours could be wrong...
Cheers,
Mike