Looks like responses are all over the place. No surprise here. It's an individual thing and no right or wrong answer. For me personally, amp & pre amp same brand. Rest doesn't matter.
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.