One good quality with support and one is substantially less. I'd choose appliances independently. The best product without regard for matching. Viking doesn't have anything at the top. Sub Zero is a good frig. Viking would be way down the list. Wolf ovens have had enamel chipping problems. Miele is my preference.

not Viking

I agree that you should choose each on function. No need to stick with the same brand.

I would never have a Viking fridge and Wolf doesn't make one for starters.

Range vs cooktop? Gas? Dual-fuel.

My best comparable would be a going to a car enthusiast forum and ask MB or BMW? Shouldn't your first question perhaps be sedan vs SUV?

Personally - Subzero, Bluestar, Miele, Sharp, Haier, Miele.

I even have 5 brands of plumbing fixtures I think - Grohe, Delta, Newport Brass, Moen, HansGrohe.

In my area, sticking with one brand = spec house. Could be $2M, but spec house and built like one....

SubZero started making Wolf cooking appliances in 2000 so I would assume the OP meant Wolf for cooking and SubZero for refrigeration. Their Cove dishwasher was introduced last year and looks pretty good.