I think Quiet is perhaps #1 most important feature, a big reason I feel matthews did so well early on was because IMO they simply had the far quietest bow and still continue to excede in this category.

Quiet has nothing to do with follow up shots IMO. it has to do with deer not reacting to the shot. Sure a faster bow will get the arrow there quicker, but really whether were talking 320fps or 350, that advantage is null, I think you would need a 500fps bow to see that advantage/reaction time to game, ie where sound wouldnt matter, or someone posted once that you'd need a bow going like 1500fps to make sound negligible.

So really sound/quiet is crucial. You want that deer to hear nothing but the arrow moving....not your bow etc....and ideally by the time he hears it that arrow is in him or just about.