RE: 280 rem or 270 win
Bothfine cartridges, itboils down to usage and ammo. I like the .280 as a reloader and especiallyif more than deer sized game are in it's future. If your going to be deer hunting onlyand buying factory ammo the .270 would be a better choice. If your going to buy factory ammo and hunt large game I'd look at a few others instead : 7mm rem mag, 3006, 300 wsm or 300 wm, etc.
I own a .270 and 7mm rem mag, both are fine cartridgesand both have been used for upto moose sized game. Howeverthe .284 bulletis better suited for the larger game between the 2.