I have one and I love it.
In my not so humble opinion,using oneinstead ofa peep for 3D shooting probably isn't going to help one bit. The real value of it is in the woods when you're making those ackward shots that require you to toss your target stance right out of the treestand.
Ihad a deerthat had walked past my stand to my left.I'm a left handed shooter so picture me, standing feet facing foward, twisting back around and trying to aim at deer while also not hitting the top part of my climber. The hind sight instantly shows just how bad I'm torquing the bow. Make a few body/arm/hand corrections and you're back in the game. Thwack! Perfect hit.