Well Troy, I'll throw a couple of coins your way.... I have a '79 GS 750 and a '77 KZ 1000.... not a 650 but I think some what simular.... The my GS is super and Suzuki still had some parts for it. I liked working on my KZ better I think because I like saying KZ more than GS. The KZ has a mystique and I have had little problem finding parts. I would say either would be a pleasure and any Suzuki I have ever owned was just bullet proof. But it has been easier to find KZ parts (even have a few KZ650 parts here if you need them)... the one to get would be the one in the better shape then just cafe' away !!!
I'm sure these ramblings have helped you descide...
