I just read through this thread, and I like alot of the responses.
Even when I shot wheels, I would take quiet over fast any day. No bow can shoot fast enough to beat a whitetail's reaction, IMO.
With that being said, there are countless other variables that should move the light in our heads from green to red, or vice versa, at the moment of truth. Body language, angle of shot, distance of shot, etc.
I dont think there is a right or wrong answer in general. It is about what works for you, what you are comfortable with and efficient with. If it is a skinny string, so be it. If it is a thick one, more power to ya. I guess Im trying to say I find it hard to believe 2# of KE or 5 fps are going to make or break a hunt. When you are shooting at an animal, know your equipment, it's limits, and your limitations with it.
Maybe Im too new to be worried about it...