Better as in stronger? Ive heard more cases for straight cut being stronger than the other way around. PPGs straights are supposedly stronger than their helicals. Ive heard claims of 5-20% stronger. But others claim that helicals have more contact area between gears, so any stress that they come under is dispersed over more teeth on the gear, making them stronger. Id say unless you are building a monster of an engine to go in front of that gearbox, youll be ok with either. You just have to decide whether or not you can live with the whine of straights.