Kelly,
Good bunch of heads you chose to compare.

Our resident broadhead expert " 5 shot" has done some extensive testing of the various expandable and exposed blade broadheads on the market today. I suggest using the search function to find some of his published results. I know he had the Snypers rated as the number 1 mechanical there for awhile but I am not sure if that changed since the last time I looked.
As for my experiences, I used the Snyper last year with good results. I prefer to use the Steelhead and Hammerhead because, in the case of the former, the more rugged design and, in the case of the latter, the larger cutting diameter.
Hope this helps.