Transmitters
Regarding 2.4Ghz it did used to be the case that you had to buy the very costly manufacturers Rxs.
However in recent years the position has changed and there are now several alternatives from independent suppliers that will work with specific transmitters. You do have to check that you have the correct protocol for your system, but most re-sellers make it plain in the ad and specs.
An example I use is the TRF6 from FrSky which works as well if not better than the Futaba versions for thier FASST system as used by the 6Ex model. Price is around the £20 mark so similar to other offerings.
Many now use two way systems that allow battery, temp and speed info to be monitored. This is useful if using LiPos as you can bring the model in before the auto shut off strands it in the middle of the lake. The rx also allow for daisy chaining of rx giving up to 12 channels, useful if you have a large scale model with multiple on board working features. I use a Taranis tx which really opens up the possibilities with its programming capability.
Like Derek I find the Spectrum programming challenging, but fellow club members use them and they are a nice solid piece of kit.
Dave
Live long and prosper
Dave