I have owned and still own some of each. I liked my old flat-bolt Ruger 77 so much that I wore out the barrel [6mm Remington]
I have since rebarrelled it and continue to enjoy it. [same chambering]
At present I have 4 Weatherby Vanguards, 2 S1's and 2 S2's. They are just great rifles. [except for the factory triggers on the S1 rifles]
My S1 in 270 will cloverleaf with, not just one, but 3 different loads I have tried.
My S1 in 300 WSM is much the same. The S2 in 30-06 is astonishingly accurate with both 165 and 180 grain bullets, and the 150 GMX/Ramshot Big Game load will make a ragged hole with 5 at 100M.
The S2 in 338 Win Mag shoots 1 moa or less with the 210 Partition, the 210 Scirocco II, the 225 Partition or Accubond, and the 225 Hornady FBIL. What is not to like?
I say keep the Vanguard. It is likely to be the best shooter, but it will depend. Some of those Rugers are very accurate also. [Particularly the Mark II actions]
Regards, Dave.