I would like to "echo" what ram3500-RCU said...usually, with "stronger" (higher torque) servos comes some amount of increased precision and reliability--not only "out of the box," but in the long run too as stronger/better servos may have ball bearings and last longer as they may not be working as hard. "Standard" servos are definitely fine for most .40-size planes and some .60-size planes as well--depending on their intended use--Sunday sport flying--just "poking holes in the sky," stuff like that. But if you prefer more flight precision or if you fly more aggressively, then better servos may be required.