stock vs stock, it's not QUITE as tough as the GT, but there also aren't the parts for the Rush to bulletproof it like there are for the GT.
Now, the Rush I have is the old Rush, not the Evo, but I've got experiance with the Evo's T15 (i hate it, much prefer the TTR 15 in the GT)
overall, I think the GT is just a flat out better truck.