Looking to buy a new rifle in one of these calibers, what are the pros and cons of each????

What you plan on using it for?

I have both calibers,the 7mm-08 has less recoil and that is what I would pick. Check out this site...

http://members.tripod.com/sed88/rem7/

Mainly Whitetails or Mule deer, might make it to Alaska for Caribou. I have a 300 win mag for elk.

One is a long action and other is a short action.

280rem is almost a 7mmremmag, and I know several folks that find accurate reloads that exceeds some accurate rem mag loads. 7mm-08 is one of the most ideal whitetail calibers, but only expect 2700fps for a 140gr bullet. 280 recoils a little more. Thats about it.

Here is what I do in your situation. Take a coin and flip it in the air, heads 7mm-8, tails 280, cause none of the animals will care you shoot.

I prefer the 7mm-08,but they are close.Figure if you want short or long action,and then just buy which ever rifle you like.

As the other posters have responded, there is not much difference, especialy with lighter (120-150gr)bullets. I personally would favor the 7mm-08 if I were you, as you already own a .300 mag.
Will

I bought my first .280 Rem. around 1963 and hunted with it for years. I then moved "up" to a 7mm Mag and also hunted with it for many years. I've now moved to the 7mm-08, and find it much more pleasant to carry and shoot. Most game taken with any of these were whitetail and groundhogs. I have loaded for them all,and settle on what the individual rifle likes to shoot the best with respectable velocity.
As others have said here already, flip a coin, or choose between the long action or short. Either one will kill deer-sized game quickly and cleanly. I'm sure you will enjoy whichever you choose............

As BC said, the main difference is the length of the action. However the 280 is a bit more versitile and will handle the heavies 284 bullets a little better. Either is great for game up to and including elk out to 300 yards. The 280 will give you another 50 yards or so. I have owned several of each.

I would go with the 7mm-08 because with the 280 you will kill any deer out there but you are limited to what you can drop with it. The 7mm-08 on the other hand is a .308 cal cut down to a 7mm bullet, so you will get the power of a 308 pushing on as lighter 7mm bullet wich means more fps equals more ke equals further shots equals better knock down. They both are good guns so its totally up to you but I say 7mm-08