I've been an airtronics fan boy since they they first released the m8. The M12 is a fantastic radio system, and it has several configurations on how you would like the radio to feel as it has the drop down you can also utilize if you want a different feel.
This in my opinion is what you should go with, but I completely agree with the previous comments on that getting some stick time with each one at your local track would be the proper way to make your decision.