I just got rid of a GZ250 and upgraded to my Savage.
The GZ is a really good bike, it just doesn't have enough power to be a truly all-around utility bike. In other words, yes, you can run the interstate with it, but you're not going to have much throttle, if any, to get yourself by another vehicle if you want to pass.
The GZ suffers on hills. You have to constantly work that shifter to maintain forward speed. The Savage, at least mine -- will pull hills in 5th gear, plus pass cars on hills (we have a three lane hill near us that is two lanes up hill and one lane downhill).
On the other hand, the GZ is flat out bulletproof. You can't tear that sucker up. It served my purpose well to learn on, but now its on to greener pastures with the Savage!
Tom