Two schools of thought. Buy the best of each appliance or match brands. I think it is a personal choice based on finances and ratings as long as the colors match. I prefer in my price range to match (except my hood). I have all kitchen aid. All out pieces were rated well at the time so it worked. The kitchen I grew up in had a Viking commercial range/oven, Bosch dish washer and a sub zero frig. Higher end than what I have and a perfectly higher end kitchen. Good luck.

I go for the features and reviews - appliances aren't cheap, I don't want something that matches but falls apart and needs to be repaired all the time! If it turns out that items are from the same brand, I suppose that's great, but it's not a particularly important point for me.

(Exception might be with some of the super high end lines, I can see how there might be a bit of a status benefit to matching certain items, like a Viking hood and a Viking range? But even there, I'd want to make sure the hood was the right one for the job before buying it just because it had the Viking logo.)

That said, there are definitely people who pretty much never actually cook, so the market for the property comes into it, too. One of my friends in NYC uses her kitchen for proper cooking exactly never, like most of the other people in her apartment building, so if I were redoing one of those units I'd go with whatever looked best aesthetically - which is likely to be brand matching since you'd get exactly the same color/finish/design elements - since probably no one will notice that the oven is awful.

For resale, middle price range is best.

As long as they match, I think it's okay to mix it up.

when we did our kitchen - we chose stainless steel and found the finish was a little different so had to be aware especially when they could be close to each other - we chose to do all one brand for all 4 - MW, fridge, DW and stove
stainless was probably not a good choice with teenage boys who always are in the fridge

I like them to match if you are able to find what you want in all the appliance - not always possible

I would choose based on features, reviews and looks, not brand name. But, sometimes you can get some really good package deals when you buy all the appliances at the same time.