i've got 2 twin velineon e-maxxs, and they are VERY reliable. Traxxas' turnaround time for esc or motor replacements are about 10 days door to door but i've never had one problem with the twin v setup. it's got ENORMOUS torque and it's ridicliuosly fast. I can get 60mph with it if i run 8K 3s lipos and gear 54/22. I run 2 12V fans on the motors with 2 800mah heli lipos to keep the motors from overheating. i almost never see temps over the 160 range.
here's a pic of one of mine, which is not the conventional setup:
and my other one which is my basher, setup to run 3s 5K lipos and is geared alot lower so the fans arent all that necessary:
I tried the MMM, but i needed something more reliable for the time being.
I've found a GREAT esc in the LT-10S (Lutach's esc) with my neu 1515 1Y setup on 6S. the thing is a MONSTER. It's faster than the twin V's, and it's alot of fun. i've had about a dozen runs on it, and it's been flawless. I've very happy with it.
here's that one:
hope that helps.