I plan on trying one this year during the off season. If you hunt at night (pigs) a peep will only hinder you. I also had 2 shots at 2 very nice (read big) bucks I could see outside the ground blind, but could not makeout through the peep at dusk. I think because it was darker inside the ground blind than outside the light was playing tricks with the peep.
With a no peep I might have tasted Pope and Young for the first time.