I tired one of those peeps with a fiber optic circle and couldn't see anything through it in low light. The light from the fiber optic drowned out everything behind it. But that was only a few years ago. Someone with younger eyes might have better results.

If you really want to have a chace of hitting something in low light, learn to shoot barebow out to 25-30 yards. All you have to do is develop a secondary anchor higher up on your face, so that you're looking under the peep and front sight. Then you have something to fall back on. When you find out you can't see to shoot, simply raise your hand up to your secondary anchor and nail it.

It's only happened to me once while hunting (because I've never used sights on a hunting bow ever again) but on the 3D courses, I've been in situations where I could see the animal plain as day, but either couldn't see the sights or couldn't see the animal behind the sights. Not being able to shoot because of the sights is ridiculous.