There are plenty of bullets to choose from in .277" diameter. The .270 AI is easy to load for, and easy to shoot. In a long barrel you will gain 150fps or more. In a 22-24" barrel you will likely gain 80-120fps. We have taken many sage poodles beyond 1000 yards with 135gr. Sierra MatchKings or re-sized 150gr. 7mm Berger VLD's. I can push the 135gr Sierra to about 3425 in a 30" Kreiger. The 150gr Berger will safely fly 3275 from the same barrel.
Berger is now producing a line of .277" bullets, removing the need for expensive bullet sizing equipment. Is there a real difference between the .270 AI, 6.5-06 AI, or the .280 AI? Not really. There are plenty of good components available for all of them. All of them have similar trajectories. All of them are capable of good accuracy and precision.