I have one and I love it. I'll qualify the following with the fact that every deer, of many, that it has killed would be just as dead with a 30-06. Any elk I might hunt would also be just as dead with a 30-06. If I get the opportunity to hunt moose, I will use my 30-06.
I fell in love with the ballistics charts before some of the .30 cal bullet improvements came along. When your premium bullet selection was basically the Nosler Partition or Speer Grand Slam, the .280 had an advantage at longer ranges, especially loaded in a Mauser 98 or other strong modern action. It was really a bit of a pipe dream for me, until I lucked onto a gunsmith special in this caliber. It was a K98 action rebarreled some time ago with a nice Shilen tube. The price was right, a semi-inletted walnut thumbhole, buehler safety, some decent glass, and I've been a believer in the round ever since.
Although any ballistic advantage is largely theoretical for my particular purposes, it's fun to be a bit of an oddball. It does throw a lot of penetrating, game stopping power downrange with manageable recoil. As others have eluded to above, I can fire high SD bullets at a useful speed without kicking my own butt. Other than that, I guess it's just fun to be different. Hopefully it doesn't get too popular, or I'll have to shop a .284 Win or build a 7x7.5Swiss or 7x54R improved in order to not fit in. That would be a whole lot of fun!
Bottom line, if you want an interesting caliber that does 30-06 type jobs better than the .270, and .270 type jobs better than the '06, the .280 is for you!
So long as we're sharing some pictures, here's mine, "The Death Ray" in it's natural habitat on Buck Hill
View attachment 814869