I have both the Quark and the MGM 16016. I actually prefer the MGM. I have run it on 5s lipo with a 7xl Feigao and ,at least for heavy duty bashing, it has never thermaled. And that is without a fan! I use a 51/11 gearing for monster wheelies and climbing power. Both run very smooth and both have good LVC properties. One thing I like is the replaceable motor and battery leads on the MGM.

I had the mgm 24160. It operated great on the 6s. Had no issues.