I have used both for turkey hunting. I switched back to the 3" load. I didn' t see any great improvement. The 3" loads use the same amount of powder as the 3 1/2" loads (not all but some of the stronger of each) only differnce is more shot. This can cause more open patterns on the 3 1/2" ' s (again not all)
There is a really good article on this in this months issue of Turkey Call actually. Good article. I think if you spend the time with either gun at the patterning board with differn' t chokes and loads you will find the " dream" combo. Mine just happens to be with Federal Premium 3" #5' s