castle creations ESCs just don't seem to play quite as nice with the Spektrum stuff as other brands but using a capacitor on the receiver usually clears up issues.
I personally use the MMP pretty much on all my vehicles include 1/8 electric as I like its versatility. I also like the fact they believe in there product enough to offer a 1 year warranty.
Thats not to say the other stuff is bad, they have excellent customer service. But to me, having a longer warranty matters with all else being generally equal.
The MMP for the money (can be had brand new for close to $100) gives a lot of bang for the buck.