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

@mattw73 my system kind of happened by fate.  I met Hans when he was developing his amplifier at before he started Infigo . He ended up doing a head to head with my Kr Audio stuff and I was so blown away I started helping him out at Infigo.  I helped him with his cabled line and got all of his components after he blew mines out of the water. After this experience I think it’s great when you can get all of your components from one brand. I’m blessed to have the components and cables from one brand which has been amazing sound wise for me.  I was mixing and matching before that. 

I often have the urge to mix them up, but the speakers refuse to play my albums. 

Mix and match. Each component has been chosen separately. Also, the manufacturers chosen don't make all components. For example, the speaker manufacturer doesn't make a CD player. I have settled on one manufacturer for interconnects and speaker cables. Power cables are a mixture. I'm very happy with the sound of my system. I can imagine that it could be improved if all of the cables were from one manufacturer, for example. 

Brand Synergy:

It seems that there is much less brand synergy at entry level, but can increase with better parts, engineering, and accompanying costs.

It seems less brand synergy for tube gear than SS

I wonder if some brand synergy is “designed” to work better with same brand components, while other brands design components independently.  

Depends on the system.  With my main 2.2 music only setup I have Rotel separates - amp, preamp and CD player all in the same MK II series.  The rest of the setup has different brands.  My Sonos systems obviously have all Sonos components.  All of my other systems are mix and match.  I also mix and match new and used components.  A fun part of the hobby is mixing and matching.  Adding different equipment from different manufacturers over time.  That’s one of the reasons I prefer separates more often.