Always figgered a guy with a .270 had little need for a .25/06, myself. The .25/06 makes a nice filler for someone with say, a .223 and an '06.
The OP mentioned SD, but recently I read somewhere that the SD that really matters is the SD remaining after expansion. Good point I think.
Something else that occurred to me is that the heavier slugs have more weight to "give" in the form of fragments to fly around inside tearing stuff up. Math ain't my strong point, but I believe 20% of 150gr is pretty much 50% more than 20% of 100.
