Davo, everyone <tips his hat>
I've worked a bit with a number of Weatherbys in: 257, 7mm, 300, 340, .30-378, .338-378, and .460. Oh, and a 7-08.
They CAN be very accurate. But, and here's the catch, for over $1000, a lot of rifes can be made accurate. When you say "long range", what does that encompass? In other words, if the range is 600 yards, the 7mm Weatherby or 300 would be very good choices. You could go with a .30-378, but you're liable to burn out the barrel before you learn what the gun likes!
I'm kidding {sort of}. I wouldn't recommend those monster rounds in 26" barrels and rifles of factory weight--it's not your BEST move, I feel. As for Weatherby versus Sako...balls, let me think before responding. I have owned three sakos, all very nice, accurate weapons, for factory firearms. They're good. Damned good. Really, the only faults with the Weatherby rifles are freebore, some people don't like the nine locking lugs, additionally, but I have SEEN Weatherbys that have shot mighty good. Mine do; I have a .257 that [actually, two], one with minor stock work, a little TLC on the trigger, some strange lapping methods [anyone ever try lapping a barrel with lead bullets using JB as the lube?], will easily hold >1 MOA groups out to 600 yards. I feel if the weapon had a stiffer barrel, it'd easily do even a bit greater on calm days [also, .257 bullet selections suck, in my opinion]. My Sakos have done fine, also. IF I were to give you some honest advice, I would say get something that lacks freebore. In a weatherby, you're going to get the short end of the stick, because all Weatherby designated chamberings employ the freebore [for other markers' rounds, they chamber according to the standard spec.] Here's the part where things go limp; if it's NOT a Weatherby designated chambering, the bastards slap a 24" barrel on instead of a 26", and in magnum chamberings, obviously, you'll have reduced velocity and more importantly, increased muzzleblast. The Sako's, usually, employ a 26" barrel on their target series in mags, but not always! Make sure you check. And if you go with a Weatherby, get an Accumark--heaviest barrel contour. You may also want to check out Remington's Sendaros...I haven't heard TOO many complaints over those.
Luck be with yee whatever thou chooses! I learned the hard way; spend a few extra dollars on a used but nice rifle, rebarrel, and teach them ol` rednecks you call your friends some respect!!! Yeehaw--and Merry Christmas to all.
Dave