I have owned Airtronics radios, the last being a M8 a while back and they are quality radios no doubt. I'm sure the M11x is a great radio, however being a long time Futaba user I naturally replaced my 3PKS with a 4PKS. The 4PKS is awesome, I can use it in every vehicle including my 1/5 on road and boat both which require 4 channels. The new 614FF RX is tiny, I picked another up to put in my pan car just because it's so small. The TX is well balanced with a great wheel and trigger feel, it is high quality all the way. I use mine with 1/8 nitro on and off road, 1/10 electric on and off road, 1/5 on and off road, and it will be used in a boat as well. This radio has every feature or function you could possibly need and several that you'll probably never use...