I use flat base in my 22-250 to 500 yds. They stay sub MOA to that distance. Haven't used it farther than that, IMO that round isn't made for much more. In my 30-06 however I use boat tail Hornady A-max. They shoot 3/4" at 100, and I'm sure I could tune them better, but I don't have enough spare time to tweak loads. Once I get them sub MOA I usually stick with that.
I think if you are shooting less then 500 yds, shoot whichever bullet gives the best accuracy out of YOUR rifle. In other words, try a few different ones until you get the best combo. You won't know which one is really better without shooting them.
Clark, why is it that you said "never let an expender ball touch your brass"? I have never heard that one, although I don't spend much time on forums.