I use a spring centre on all my models bar one because, as JimG says, its easier to find the neutral point so your boat doesn't wander off on its own when you think it's stopped. The only model I use a ratchet on is a submarine - it's quite slow so easy to keep track of and with 7 functions controlling dive planes, rudder, ballast tank, compressors etc there's enough going on without worrying about holding a throttle in position.
Ralph