I would say USGT. I like the choice of bodies much better, and the new crop of 21.5 motors are legit.
I run a 11 yr old TB03 ( though highly customized but still 11 yrs old ) and keep up and on par with some really fast drives sporting the A800 and Xrays.
I run a Fanton 21.5 Hobby wing just stock, Savox servo and Turnigy lipo.
You don;t have to spend a ton to be competitive. Just practice and understanding to set the car up to how you drive, you can get tips and tricks from other drivers, but work on setup for driving style.
USGT is a blast.