This year I used both. I found little difference. Here are some pics of heart shots by different broad heads this year.

This is a heart shot with a Nap spitfire 100 grain mechanical 1.3/4 inch cut, from 35 yards.


Here is a shot from a 100 grain tikki fixed 1.5 Inch cut at 27 yards


The texture of the heart of the mechanical was rather ridged and the deer ran about 60 yards. The texture of the heart with the fixed was mushy and the animal walked 10 yards and fell. Personally I like both. Both did the job well. Both were pass throughs.