I've killed deer with both and IMO, were pretty similar designs.

I now shoot the Impact Cosmic XL
I can't remember the name of the Cosmic I had, but it was a moveable single pin sight, all metal, very similar desing to the Cosmic and about the same price.

I choose impace b/c I like the clear aperture and b/c I have contacted their customer service several times and they have helped me out. I just ordered the crosshair aperture to try with my Cosmic frame. I hope to start shooting soon and find out which one I like best.