The PCM receiver is a better receiver than PPM.
It provides better sensitivity and greater noise protection.
Does it hide glitches? Yes. That is one of the things that make it better.
Its a bit harder to range check simply because it has a better range.
One simple way:
Set the fail safe to cut the throttle to idle.
Start the engine and with your buddy holding and the throttle at 1/2 walk out until the throttle goes to idle. Thats your range.

Do you need PCM? No. PPM works OK.