I have them on every bow I own (4).
You don't need to buy a 3D target. The sight includes a paper target and really all you need to do is figure out how much space you need to visualize on the animal; works for turkey, deer, elk, etc. They also work as a "traditional" sight with the tick marks.
Aaron runs a 30 day return policy. Only thing you'd be out is the shipping cost if you decided it wouldn't work.
I like to think of them as the "ACOG" of bow sights.