A lot of people have them, and love them, whereas another lot of people wouldn't touch them with a bargepole......read "wouldn't trust anything cheap chinese"
I am firmly in the former group.
I have a FlySky FS-i6, and have never found any problem with it.
I have used it for boat, car, Heli and quadcopter.
I also like the fact that receivers are not too expensive, it has telemetry facility (ideal to monitor the voltage of onboard battery), the footprint of the Tx is small, therefore easier to handle, and full 1.5km range (wow)....whats not to like?