For what it is worth..
I have used ESC from a variety of chinese comapnies for my planes and helicopters. For cars; Castle, BK, Losi, Jeti, Schulze and MGM.
Regarding MGM: Unfortunately not the new series of MGM, but the other series has been fantastic. Super-smooth..., with good brakes. A lot of punch and really good feeling on the throttle. I have really miss-used the MGM and turned off all the protective features - never any probs at all.. Once it became very wet and stopped, but after drying up it worked perfectly again. The temp-protection cannot be disabled, so I have been running it up to 100C many times - it just stops, beeps and after a reset from the radio and a few minutes of rest it starts again
I know it is not the same series, but the brand has worked very well for me. I'm also thinking of the 40063 for a coming project