the stock ESC is a piece of junk. it will work just fine for a long time, provided you use the stock battery and dont try to put more power to it. you can get away with using a 6cell 7.2v battery with more MAH for longer runtimes, but you cant use a battery with more voltage.

i just bought a used volcano epx PRO. that is the brushless version. i have read that the drivetrain is very tough, but that some of the a-arms, shocks and such parts are not strong enough. i will test mine and see. im pretty good and modding such parts to make them stronger anyway.
the epx pro costs $190 new. the main difference is you get a novatech brushless system instead of the brushed. its WAY faster.