For non-keyboard access to MIDI, I am looking at guitar synthesizers to meet my needs. Converting a guitar signal into a MIDI stream has many benefits - generating lead sheets, "Recording" information instead of audio, and rapid key changes.

Roland's newest Guitar synthesizer is the GR-33. Is it a dramatically better machine than the GR-30? And is the GK-2A tracking any better?
eBay has a few used items, like the GR-50, and GI-10.
It's a bit confusing since Roland was inconsistent with model naming, to figure out what came first, or what is "improved".
GR-09,1,50,30,33? GM-70? GI-10? G-700?

Lastly, if one wanted to buy a new GR-33 + GK-2A, what's the b-e-s-t deal?