Well, I was going to post pics of a couple of my groups but Mac's are better!
Scibaer, those are fair questions. I bought a .280 because I wanted a fast, flat-shooting 7mm without having to deal with the noise, recoil, etc., of a magnum. My current load with the Speer 145 gr spitzer averages 2998 fps, and I had a couple in the string go 3020. If you can find some honest numbers on the 7 Rem Mag, I think you'll be impressed with the .280 Rem. The Speer manual says something to the effect that if you own a good .280 there's no reason to trade it for any of the 7 mags. In medium weight bullets for whitetails, the difference in the .280 and 7mm Rem is very small.
I've only done the washer thing to my .280, and I've shot several 100 yard groups under 1/2".
3 of the last 4 deer I've killed have been with that load in the .280, and it's been impressive. The longest shot was 172 yards, the shortest was 60 yards, two were broadside shots, the 60 yard shot was quartering toward me. On the 172 yard (measured with a rangefinder later), the bullet went through both shoulders and the deer went about 50 yards before piling up-- the other two were bang-flop, pass-throughs on all. All 3 deer were in the 150-160 lb range.
With the 26" barrel it's not quite as "handy" as the other handis, but it's still shorter overall than my Weatherby Vanguard. Unless you're in a small shooting house that's not really an issue in the field, and the long barrel lets you maximize the .280's potential.
Nothing against the .243, but this 7mm is more potent deer medicine without being overkill and the .280 Handi is pleasant to shoot. Hope that helped.
Rick