I have had great results with the Spitfire 100gr. As a matter of fact I shot a deer this morning at 34 yds, my longest shot ever on a deer and got a complete pass thru. I have to tell you though that he was standing broadside and I did hit the sweetspot, but it was a pass thru nonetheless.
Personally, I think those that are not getting pass thrus with some of the better mechanicals are shooting setups that dont have enough KE or are just not hitting the sweetspot. I dont think you are going to get pass thrus with any broadhead, fixed or mechanical if you dont hit the right spot.
Just my opinion.

hc4runner
MO. bowhunter