ORIGINAL: Strykaas
I would move on to 6V but I've read so many servos failure reports which are probably related to running on 6V... So I'm kind of reluctant !
I would love to hear 1 credible story about a servo that is rated for 6 volts that has failed for using 6V battery. Almost everyone who flies giant scale aircraft uses 6V batteries, usually 2 of them to their receivers. For the tens of thousands of servos being used by giant scale guys, servo failure is rare. We have a whole lot to lose in a giant scale aircraft than your little .50 size airplane
I'd be curious to know what servos you are using now and to know your flying style (some aerobatics, aggressvie aerobatics, Sunday flyer, some 3D, down on the deck 3D, Basic IMAC, advanced IMAC)
If you are not moving your sticks on the radio any faster than the servos are already moving, than faster servos are not going to do any good. If you are very aggressive and moving the sticks very quickly, than faster servos may be needed.
I don't think it makes any sense to put $100 servos in a small airplane, if you really want to improve how your small airplane flies, maybe it's time for you to get a giant scale airplane