I just switched from an MT4 to an M12S. They both can win and are very good radios. I feel the M12S has lots of little "upgrades" that many don't need. The size could be good or bad. The M12 weight is nice and nothing like the older heavier versions. The drop down wheel is nice, but didn't make me think "wow!" What I do really like about the M12 is the race mode features that allow me to change a huge amount of set up features with one click. I also really like the additional sizes of the break lever. My trigger finger feels so much more locked in with no slack when pushing out to break. Also, once you get to know the menu OS it is nicer than the MT4.
I've read several reviews that say the M12 has a more connected feel for steering, but I feel the throttle response is where I feel more connected than the mt4.

Again, none of these things may make you any faster and for the price it's a huge thing to consider. I will say that right now I'd rather have my M12S than another car or the Mt-4 and some other gear.

Combined with a good coupon code at TH the m12S can be had for about $480.Factor in the M12S comes with a LiFe battery that's a good deal over the M12.