Do you use one brand of electronics or are you mixing brands what has worked best for you?

Still should be noted, that is opinion and will not change. 

 I started collecting my system in 1980. Still use same preamp (recapped). All other componets added or changed the past 4 years since Ive been an empty nester. Ive gotten the best I could get with my budget, as a result it is all mix now.

The pre amp & amp are probably the only two components I would really like to match, but all and all it is a nice mid-fi system for me.

Mix and match. Vinnie Rossi tube pre with Pass Labs solid state power.  Class A and dual mono common theme. 

I've done both, and was happy each way...but now an Integrated Amp w/phono, and very happy to have 3 less boxes...

My unprovable theory is that if you find a house sound that is perfect for you. All the same components should outperform mix and match. I cannot prove it. But to me, each component must be subtractive in some way. Say your first component is lean, and the second really warm, and third lean, and amp is warm... aren't you loosing nuance at each component when they are of different character. I will not defend this. It is just a thought experiment. 

@ghdprentice  Very adventurous thought process — I like it. To add to that, my view is that any coloration (anything non-neutral) acts like a filter that accumulates or cancels out across the entire signal chain (cables included), ultimately altering the system’s frequency response. So to minimize that effect, it’s preferable to keep components as neutral as possible and preserve that neutrality until the very end of the chain, where you can make intentional adjustments to the timbre or overall tonal balance for better coherence.  This principle could be duly applicable to a mixed and match system as well.