Ijust ordered 3 or these for another project: but Iwish I had waited another week or so to
see what UltimateRC has to say about them. They seem to be about the same value as a HobbyKing ESC(cost a bit more) but I'm willing to try something new, and their programmabilty looks interesting.
I ran the stock setup with 3s lipos and had no problems bashing offroad - the motor temperature never went over 60-degrees C and the ESC was barely warm. So you probably don't need a new ESC with the stock motor. But I'm putting in a spare Castle 4600kv for some speed runs, so I'm going to pull the stock motor+ESC for another project and put in a BrushlessHobbies 120a.