personally, I'd run the stock esc unless you have problems with it. I have one of the early models without the heatsink and it has been trouble free for a full year of flying. Its powering a jgf 500th which is another good choice for motors. It probably falls just short of the scorpion if you ask me (in the power department anyhow) though it is very efficient, lightweight, and runs pretty cool.

My stock esc has at least 500 packs through it and since I programmed it the first time it has pretty much performed flawlessly.