Been eyeballing one of those new Rem 700 Long Range rifles. I'm cheap, and want something with more legs than my .308. Looked at the available calibers, and narrowed it down to either the .300WM or the 7mm Rem Mag. Crunched all the numbers for the loads I planned to use. The .300 has more punch off the line, the 7 has better BC's. At 1k yd, it's kinda 5/4 and pick'em. What really swung it for me was 2 facts; the 7 uses, on average, 5-10gr less powder per round to produce the same velocity, and when I plugged my numbers into a free recoil calculator, the 7 produced about 16.5lb free recoil, while the .300 produced about 21lb. Rule of thumb is that anything over 20 is uncomfortable for most people. I plan to shoot paper a lot more than animals, and sitting down behind a gun with the intent to fire more than a couple rounds means recoil factors in.
Just my personal experience with research. As others have stated, anything in the 6.5-7mm range would give superior ballistics with less recoil for punching paper at long range. If you were shooting teeth, claws, and horns, the extra thump of th .300s and up would be reassuring, though.