I own 2 7mags, 2 280s, 1 757 and 1 708. Is one better then the other? depends if i want to shoot a deer at 500 yards id take the 7mag hands down. If i wanted to shoot something bigger then deer and felt i needed a 160 grain bullet the 7mag or the 280 would get the nod. IF i was going out deer hunting and knew for a fact the longest shot i possible could have would be under 300 yards id take the 708 or 757. Personaly I dont think theres enough recoil with any of them to make it an issue. Even a 7 mag kicks no more then an 06 and if you cant handle that you should be spending more time at the range and less time on here giving your expert internet opinion.
back to the original question. the 280s more powerful. You can juggle numbers all you want to defend your baby but the 280 holds more powder and shoots the same weight bullet faster. that translates to more power. You can argue that its not much more then a 708 but then you can argue that the 7mag isnt that much more then the 280 too but if you went by that mentality you might as well use a 243 as its pretty close to a 708 or a 22250 because its pretty close to a 243.