22-250 if you don't care about barrel life. That being said both will require reloading so I'd throw 22 creed/22xc/22x47L in the mix as well. If you plan to run a dam setup like an aics both will require tweaked mags.
I have both, and both shoot heavy bullets. 75's on a 1:8 in the .22-250, yielding 3200 fps. 80's on a 1:7.7 in the .223 A.I. yielding 3085 fps.
So they are awfully close in performance. The good of the .22-250 is no fire forming. The bad is it uses 30% more powder. Not really an issue for me, just buy more powder.
The .223 A.I. gets better fuel mileage, in other words.