For 18 years I raced RC cars competitvely.  I always used KO or Futaba.  KO was my favorite.

I have had 5 airplane radios in the past 3 years (not all by choice...!)  I started with a HiTec Optic 6 which is a nice radio but was somewhat limited in functionality and the display was not great.  I sold it to a new flyer after I had been flying 3 months.  These are used by almost all the guys locally and unless you move into more complex models they work great.

Then I went to Multiplex Evo which was excellent until I had a PCM lock out/run-away with it.  Luckily I was able to get control often enough to do a controlled crash and the airplane was repaired.  I sent it back and they repaired a loose joint on the antenna mount in the TX but I just couldn't bring myself to trust it after that so I sold it.  When it worked it was a very nice radio, very comfortable and easy to program (once you got the hang of it.)

Then I had a JR 9303 - excellent radio that I should have stuck with.  Rock solid, easy to program.

I "traded in" the 9303 for a DX-7 when SS first came out.  My thinking was to use the DX-7 int he spring and then get the 9303X when it came out.  I jumpped the gun way to early and won't do that again!  I had been using 2.4GHz on cars for a couple of years with great experiences.  The DX-7 did not work out for me, the TX failed after about 100 flights (luckily on the ground.)  Then after I got it back I had an Rx failure that cost me an airplane.  It was not a battery issue - it was a component failure.  The Rx just plain stopped working in the air.  The Rx was the only thing not working in the wreckage.  SS itself works great but personally I have had bad luck with reliability of the Spektrum components.

Finally I went with the Futaba 12Z.  I love it and it has been rock-solid for a full season now.  Easy to program, no end of features and when Futaba modules come out I will be able to transition to 2.4GHz.  Hopefully this one sticks around for the next decade or so!  I use it with all kinds of Rx's Futaba PCM, Weatronic, Multiplex even JR.  Never so much as a glitch in over 1,000 flights.  The only drawback I can think of is that it uses batteries like mad.  The 2400 LiIon pack only lasts about 2 hrs of on-time for me (I charge as soon as it gets to 40% remaining.)