Just bought a 7mm-08 myself. Going to shoot it for the first time this afternoon. I like the small size, short action and 7mm bullet. Also, it is sufficient for most north american game. Most 7mm-08 loads carry 1000 ft lbs of energy at 500 yards. I have read that most expert game hunters recommends a 1000 ft lbs for killing a white tail. So from that standpoint, the 7mm-08 can take deer at 500 yards. That is if the shooter can hit the pump station at that distance.
I reload. If I didn't reload, I wouldn't even consider the 7mm-08 or .280. They are $28 a box at the cheapest. As for the SD, the .270 is nearly identical to the .280. The only real advantage of the .280 is the variety of 7mm bullets available. If I was buying a single gun for hunting in North America, I would go with the .270. You can get 150gr that is sufficient for elk and you can buy 130 managed recoil to use on white tail for children and women to use. Also, most standard .270 loads are around $18 per box. From a ballistic standpoint, the .280 has very little advantage over the .270 if any and I am not sure I have ever seen .280 at Walmart around here and .270 is in nearly every store that sales ammo. The .270 is extremely popular and will be around a long time to come, don't see the .280 picking up popularity because a few people think the .284 is superior to the .277. Most shooters don't even know that. Most folks don't know a .280 is really a .284/7mm bullet. I am keeping my .270 as standby even if I use the 7mm-08 for my future white tail applications.
As for effectiveness on whitetails, I believe this is more based on bullet construction and placement than on the actual piece of brass it is dispensed from.