I'm required to shoot split by IFAA/NFAA Longbow rules. I'd shoot 3-under for closer distances if not for that requirement. 3-under moves your point-on distance closer, reducing your gap substantially for close-range shooting, making it easier to be accurate. However, beyond about 40 yards, I think everyone does better shooting split, because with 3 under you'd be doing a ton of stacking. So, when I have the opportunity to shoot 3-under for IBO stuff, I may give that a try, as the distances involved are much shorter than field archery where you have to be good out to 80 yards with a longbow and wood arrows.