split since day one,, I actually feel the difference in my bows when I tried 3 under but maybe its the feel on the pinky finger too I remember a pinch thing going on at my pinky when I tried 3under at full draw.
also, a couple people I shoot with who shoot 3 under usually fall apart on a coon course (shooting in the dark) or shooting in different postions and it leads me to believe either conciously or subconciously they are gunbarreling or gap shooting and cannot see the arrow or their form is different,,, good thing or bad thing i'm not sure but split for me eliminates all that extra mind warp stuff so even in the pitch dark, or if the bow is canted in any position OR I can be Kneeling down with my bow verticle to the ground or back the other way kneeling down and leaning back with my bow hugging my chest to shoot around a tree my target picture and accuracy is pretty much always the same.
thats just me though because I have been destroyed on the 3d course by a 3 under friend, I think he shot a 296 that day and we shot from the compound bowhunter stake with a max distance of 30yds so it can be very deadly for some people,,,,,, he hunts from a tree stand so no shooting in the dark and pretty much all his deer are clean kills out to 30-35yds I'm pretty sure his max is with a 50# bow.