I believe the xcelorin may have an advantage over the MMM in terms of higher Amp ratings - provided that the numbers on the MMM are correct.
I agree to some extent with MetalMan a comparison out on the field and some graphs to show at the end of the day would be more accurate.
There are a couple of recent positive reports on rctech about the Losi esc. Not sure if they are biased toward's losi but here is a link to one of them (post #305).
http://www.rctech.net/forum/electric...-e-4wd-11.html