You will find hat most audiophiles mix components to achieve a sound they most enjoy. I don't think there is really any advantage to using the same brand of components. It drastically limits the choices you have. Manufacturers of course push brand symetry because it sells more product for them
Benefits of brand synergy
How important is brand synergy in matching components? This not only includes amps and preamps but also digital sources from a particular brand, say Arcam or Kell. Is this "synergy" important just for impedance purposes or is there an additional sonic benefit of having everything matching? Thanks.