Depends on what you're hunting. Deer or turkey up close, I'll go quiet. Pronghorns far off, or elk, caribou or moose at any range -- they're not fast enough to jump the string, in my experience.
Looking at it another way -- maximizing penetration -- I prefer to use the heaviest arrow I can shoot well for a given animal, except lightweights like turkey and antelope. That dictates that my shots are generally quieter than they are fast.
Frankly, none of this gear stuff, although it's important, has ever been a big problem for me in an embarrassingly long bowhunting career. Rather, the challenge is finding the durned animals and getting them to stand broadside at close range!