M12 is out and M11X can be found used for a price comparable to a new MT4.

Can you help me choose the good radio for my use? I race only and need to upgrade my DX3R.

I would like to know the difference in "feel" between both radios, if anyone already compared these transmitters and could give me a feedback.. There are a few comments on the web but everyone is defending his radio without explaining why so it doesn't really help. I'm looking for good ergonomics and a "connected" feel.