Maintenance failures are unaffected by a ship's speed, only by the time since last overhaul. A ship that sits at a jump point all its life will (on average) have the same number of failures as a ship that zips around the solar system. As well, fuel usage is by distance traveled, not by speed, so you don't save anything there either. You basically don't gain any inherent advantage (or disadvantage) by making your ship go slower, although any tactical or RP bonuses are up to you.