I have 5 Mark V and 2 Sako 85's. Really like them both but I think the 85 is smoother on average. The safety on the 85 is better but kind of complex and I'm not certain where you hunt but snow and ice could be a problem with the little bolt release. The Weatherby safety's are not prone to much trouble pretty plain jane actually and you have to go off safe to unload which I don't think is the best feature. Sako's trigger is a bit better that Weatherby's on average through my collection which is all prior to the move to Sheridan. I think if I were building short action the 85 is pretty darn good and I've never heard of any problem with the 85S.
Sometimes the bolt on the Mark V action can ride on the bolt stop too high which makes it a little rough but smooths out over time or can be repaired. As has been said the Mark V action is a tank the 85 more finesse and I would say lighter. I think there's only 3 Mark V actions there might be 4 while Sako has 6 which may limit your cartridge choices with the action you decide on. The only thing that really changes with the Mark V long or short actions is the bolt slot. I don't think Weatherby has ever made a short action magnum which Sako does.
I don't think all gunsmiths are created equal with your 2 action choices they are both excellent though.
Good luck and shoot straight y'all
