I switched to 3-under last January only because Lancaster Archery teaches it for their "beginners" session, which I took. It improved my score by greatly reducing "thrown" arrows. I still shoot with my index finger in the corner of my mouth...it just brings the arrow a bit closer to my eye. When you start shooting 3-under your arrows will be low. After 6 arrows, your brain will get the message to correct that. In my case, I think it improved my release rather than my aim.