NO! Ammo availability world-wide would favor the .270!

What I would do, if you can't keep both rifles (the best solution!!) would be to thoroughly test both for accuracy, and keep the one which shoots best! There isn't enough difference between the two rounds to select one over the other for deer sized game. If you intend to shoot elk and larger critters, then the .280 will allow you to use heavier bullets. This is not much of an advantage these days, with the wide selection of premium bullets available today!!