Guess I can't give ya much more info. Other than the GT is known to be one of the most bulletproof trucks their is. And it's super easy to work on. You can get any one thing off it without taking apart a bunch of other stuff.
The rush isn't a bad truck, just not in the gt's league.
Price, well brand new rtr goes about 280 for a gt. But you can find em on ebay for cheaper ready to run. Just don't expect the motor on an ebay one to last forever. Personally I think buying from forums is more trustworthy, but you're more protected on ebay.