Looking for info on real actual delay in radio systems is hard because there is no independent data available. A very few sheets pop up some times from manufactures claiming their is better than other but no info on how test is done and if it is fair play.
So I have developed my own arduino code to do it. The arduino is connected to the steering input on the radio and also connected to the servo output of the receiver. It sends a high signal making the steering go from full left top full right and starts a timer and stop the timer when it have a servo signal that is starting to move from full left position.
Arduino code at github: https://github.com/condac/RCRadioBenchmark
Results in the wiki section on git project: https://github.com/condac/RCRadioBenchmark/wiki

The arduino program have been verified with a logic analyzer so the times are very accurate. The reason for random delay times has to do with the fact that the receivers have a fixed update rate to the servo and depending on when the signal changes and the time to next update is due to happen the time is random. This is why maximum and minimum together with average values are of most importance. also the update rate of the signal to the servo.

If you have an arduino and a radio where you can access the steering pot or connector please help me out and fill in the results with more radios.