I have had both 22" and 24" barrels on .280 Remingtons and like the 24" better for most purposes. The biggest improvement over a good old .270 Winchester is the ability to use premium heavy bullets at reasonable velocities. I like 7mm 160 grain bullets for game larger than deer, and some guys that I know like the 175 grain pills. If lighter bullets are used in a .280 there is no significant difference between it and a 270.
I do not really see the need in the AI chambering, but you can always get your .280 rechambered into an AI later if you need a bit more velocity (one reason to get the 24" tube).