I prefer Parma resistor controllers, 60ohm. Some prefer 45s. I tried them, they were too touchy for me. The lower the number, the earlier in the "pull" the power comes on. Perhaps others are "faster" than me. The higher the voltage you run, the higher the number also, and I run 20.5v.
Pre MegaG+ sets also are generally 60ohm.
Now, to answer your question, set controllers have to be cheaply made, and they are. Really, a controller is made up of a wiper that is on a "dead" unpowered spot at rest, and as you pull the trigger, you are eliminating more and more of the resistor, hence sending more and more power to the car. At wide open, the resistor is effectively eliminated from the circuit.
SO, it comes down to the execution of the plastic housing, the quality of the resistor, and the quality of the trigger and it's mount and hinge and so forth. The Ideal controllers are incrementally--but significantly--more robust that the Tyco controllers that I used prior in the execution of all of those design details.
I do not have as much experience with the AFX controllers but believe that the Ideal controllers are superior to them as well. Additionally, all of the more recent AFX controllers are 120ohm. Good for their Mega G+ cars, at 22v. Neither of which I run.
Occasionally something goes wrong, perhaps the little return spring inside, and you need to get in there and fix it somehow. Tyco and AFX controller halves are glued together. And the plastic is pretty thin. So you are pretty close to ruining the thing just to get in there. Once repairs are made, do you glue it back together? I used to wind tape around the handle for the next access. But then, tape around your controller is not the most elegant solution, as far as solutions go.
The ideal controllers have small phillips head screws that make it easy to get in there.
So, to recap, I would suggest comparing the Parmas to Ideal controllers, cost wise. Understand that in either case, you are purchasing something that is outdated and out of production. Let cost and "value", and the level that you want to invest drive your decision.
Electronic controllers are the next step up. I am old school and prefer "simple" pretty much in all things, and they look more complex than a spool of wire on a porcelain rod. And resistor controllers can be wired either way to change the direction of travel. Important to me since I run a four lane figure 8 and that works out to one track runs opposite of the other, wiring wise. Others can provide a wealth of information on those if you like. Generally they cost more than the Parmas, which cost more than the Ideal controllers. As they say, "You pays your money and you picks your poison".
