Its up to you, but I believe the consensus these days is 'Buy once, buy right'. You are better off buying a decent pair of controllers which you can reuse and transfer into future machines than tying to buy cheap. Combat is way outside what most ESC's are designed for and you will probably find you have spent as much on replacement cheap parts as you could have on one really good one.
We use Brushless in our HW's I'll admit so its not my area of expertise, but a pair of Vypers, shock mounted would be a good say to go. Alternatively, drop your voltage to 24V and go with TZ85's... though do expect them to get very hot.