Best Of Breed or Matching Components?

Not sure what constitutes "best" sound, but I will say this - I'm very happy with my Ayre stack (AX-7e, CX-7e mp, P-5xe, L-5xe). But then again, I don't like being on the equipment merry-go-round. My recent purchase of my Vandersteen Quatro CTs is the first significant change to my system in 9-ish years. 

Match a tubed preamp to a great solid state amp for a great sound without all the amp tube changing.

This from the perspective of a DIYer.

Every resistor, every capacitor matters. Not to mention every single tube, transistor, op-amp, and transformer, as well as the topology. Just this month, I had to scramble because a simple resonance tweak changed the character of my analogue front end, from being clean and precise to being cleaner but unpleasantly shrill. I did not want to lose the new-found clarity, but had to soften the sound somehow, so I changed some teflon caps to styrene, decreased the impedance on my step-up transformer, and added capacitance to a cable.

The moral of the story is, go with what sounds good, BUT, component synergy may change with every tweak.

I use the same manufacturer for all my electronics...amp/preamp/CD player.  They all work well together because they were designed that way.

I would think that matching components by the same manufacturer would have an advantage if the technologies used are somewhat unique
and quite similar in nature, or they were introduced in about the same time period.  OTOH, there may be a particular preamp that you like due to its features or ease of use, whereas amps are more or less "black boxes" with an on/off button.  Therefore, the amplifier IMO should best be matched with the speakers you like; the preamp choice may have certain features or complements your source components.  Mixing tubes and solid state generally takes more research and more auditioning.  P.S.- of course now you have combination preamp/dac/streamers/servers, and speakers with built-in amplification,
so this makes things easier (?) / harder (?). So I tend to stay with the older 2-channel stereo configuration with which i am more familiar...