I would take the blaser as they have a better reputation for accuracy.
Weatherby rifles are nice but are built for speed over accuracy.
Weatherby rifles are guaranteed to be sub moa. blazers are not. Also Blazers are not very well known for shooting sub moa. I have shot a lot of them and usually the best you get is about 1.25".The only advantage a Blazer has ove any rifle is the interchangeable barrels system and you can buy a new complete rifle for the price of the barrels for a Blazer.
And yes have and do own both brands of these guns. I also have not seen a R8 for the same price as a Mark V.
I have to ask dee have you owned a new generation Weatherby or are you making a statement based on opinion only?