I haven't shot with a string peep in years, after discovering the No-Peep sight eliminator. They're no longer available though. The company that makes the IQ Bowsight bought the technical rights to this device and now uses the concept in their new bow sight. There is however, a very similar product called the Anchor Sight (http://www.archeryinnovations.com/Main.html). The Anchor Sight costs a little more than the No-Peep but it's likely worth the extra coin due to the better adjusting mechanism used for horizontal and vertical alignment over what the No-Peep uses.
The concept is the device is attached to the riser and set up so when the shooter is at full draw and at the natural anchor point the black dot in the device is centered in the device and it has concentric circles around the dot, showing the shooter that he is holding the bow exactly the same each time. These are designed so even a small amount of torque applied to the riser is quickly evident, thus enabling the shooter to hold the bow consistently from shot to shot. If you've ever shot a rifle with front and rear peep sights you'll quickly see the similarity and understand how it works.
For the hunter there's another great advantage and that is you don't have a string peep aperture in front of your eye limiting the amount of light entering your eye. This provides generally about 15-20 minutes additional shooting time, very early morning and late evening, since you can see the illuminated front sight pin(s) and your game with greater clarity than compared with what you can see when viewing the same target in the same dim light looking through a string peep.
Since you eliminate the need for a string peep with this device you don't have to contend with peep rotation any more. You'll also gain a little arrow speed too since you've removed some weight off your string by eliminating the peep.
Just throwing this out for consideration in case you aren't aware of them.
2008 Martin Firecat Pro-X (29" DL, 66# DW), home-made TRG, new VEMs, DS Advantage/HHA Pro-5519 front sight, No-Peep Sight Eliminator, Limb-Driver arrow rest, B-Stinger stabilizer/dampener, custom upper STS, G5 Head-Loc quiver on custom mounting bracket. Gold Tip Velocity XT300 arrows with Bi-Delta 2.5" Sharkstooth vanes and Grizzly single-bevel broadheads, 498 grains at 262 fps (22% FOC)