0.1 seconds @ 50km/hr is 1.4m he is lower and faster than that on some moves
Servos on mine are under 0.1 at about 7kg and they are old tech relatively and I am still running a flybar on mine.
Biggest issue as you mentioned earlier is more likely the Brain wigging out or lagging as much as anything so you want all the other latency you can to total nil or close to it.
I still remember watching a guy I know tell about the awesomeness of very early DSM technology right before the R/X he had just installed into his Carbon shelled Heli glitch and it had a 0.5 second reboot time (early Spectrum) while he was hovering at about 10m. It was fairly graceful as it rolled over into the ground