I use 9254 on tail of my heli's which is what they were designed for.
speed is 0.06sec/60deg at 4.8V
torque is 3.4kg at 4.8V
they are rated at 4.8V only but I know guys use them at 5.1V regulated.

I've had no reliability issues (other than one which didn't like a boom strike) and the servo performs well but is 3.4kg enough torque for large elevator surfaces.