It works with any type of sight. Its only function is to let you know you are at the proper anchor point. It will also point out any grip issues at full draw.
Here is how it works. Once at full draw, you take a quick peak at the Anchor Sight. What you are looking at is a circle on the far side of the housing and a ring on the near side. If the circle is inside the ring, you know you are at your proper anchor point and you then go about your normal routine, focusing on the sight and target. It really isn't complicated at all. You glance at it for a split second once you are at full draw - no different than making sure your sight housing is centered in your peep.
You do not need a peep sight.
It is tremendous for low light shooting.
I think it is easier to shoot with both eyes open.
Shows other potential form/grip flaws other than just your anchor point.
I'm not trying to convince anyone they should try one, I just want to clear up some misconceptions about it. Again - I have one on my Legacy (now my back up bow) and I do not have one on my 337. I may decide to put one on my 337 if I am not satisfied with my low light shooting with a peep.