Price was no object for me and I chose the MT-4. Held every radio I could, 4pks, 4pl, 3pks, M11x, MT-4, a few RadioPost, all the Spektrums, and even a few FlySkys.
4pks - Liked the feel in my hand, felt good, but not great.
4pl - Did not like the feel or look
3pks - Horribly balanced
M11x - felt great, but not well balanced
MT4 - felt great, loved the balance
RadioPost- Also felt great, but not sure about longevity since they're fairly new, and they look goofy as hell.
Spektrums- felt like garbage all around
FlySky- Felt pretty good, decent balance
Out of all of those the Airtronics and Radiopost units were at the top of my list. I weighed the pros and cons of each including price and the hands-down winner was the MT-4. I've since fitted it with a tennis raquet over-grip and adjusted all the settings to my liking and it feels like an extension of my body. Car does exactly what I want, when I want it to. I couldn't be happier with my purchase, and as a bonus I got the deal with 2 telemetry receivers. I just don't think there is a better all-around radio on the market than the MT-4, at any price point.