In my test of Spring 2008, the Federal Flight Control shells gave me the most uniform patterns of the following:
Federal Premium� Mag Shok Hi Velocity Flitecontrol� Turkey Loads
Winchester Supremes
Winchester Elite Extended Range
They also gave me a denser pattern than the Winchester Supremes.
Win. Elite was marginally "denser" but not as uniform at the Federals.
In my test I was trying to compare as "apples-to-apples" as possible, all loads were 3.5-inch, 2 oz. shot, and comparing same shot sizes. For some reason, my gun/chokes didn't seem to like #6 size shot as well as #5's. My #5-shot patterns were almost as dense as the #6 patterns, i.e. I only had a fraction of the extra pellets on the paper when I switched to #6 loads.
I'm sure different guns with different chokes will get totally different results --- why it's important to pattern test your guns.