I have an oversized peep but that was not still enough for me, I learned to shoot both eyes open.
On average if I'm hunting a field edge I can shoot easily 10-15 minutes longer then I could with one eye(for the record it is legal to hunt 1/2 hour after sunset in Maine) In the woods there is less then 10-15 minutes but it is probably 5 minutes longer I can hunt and feel confident about a shot. I'm not an advocate for shooting in low light but I practice a lot at dusk. If I can't see detail on the animal then I know it's too late to shoot.

I've contemplated a no peep for a couple of years but have yet to make a switch. I like to hear some feedback from anyone who shoots with one.