Have you changed your mind about a brand? Was it you, or them?

I used to be a big B&W fan, had one stand mount after another, just before ordering a pair of their best stand mounts, attended an event at my then local audio dealer, where Totem was sponsoring the open bar, so I ventured into their room and was blown away by the Fire monitors.  I returned to the dealer for some quality time with both speakers, the Totems won "hands down".

I also used to be an NAD fan, had several of their amps, receivers, CD players and their Masters series components, but had more repairs on them than I could stand...now I know I'm going to get killed for this, but I switched to McIntosh.

Well, I wouldn't wish to do a direct McIntosh to NAD comparison, but the latest NAD mini integrateds are really nice and affordable.  Great solutions for desktop / living room systems.

Bryston.  They make great amps, and I love their DAC.  Their streamer is however poorly conceived, and I was dumb enough to buy their optical player, which basically can only be used as a CD transport .  They should stick to amps and quit trying to have a full lineup

My most expensive mistake was Apogee Divas. They turned out to be very fragile and when I heard the company was going under I bailed. Fortunately they still had mythological status so I did not do too poorly. 
Back to my trust old Acoustat 2+2's. I came to the realization of just how special they are and use them to this day. In term of active companies that I would not do business with if they gave me the stuff? That would be Dan D'Agostino. I had my run in with him when he still ran Krell. I had KMA 100's and KR 2 preamp. One of the pots in the preamp started to fail. They were a special order part which Dan ran out of and would not order more. His response was to pick up a Pot at Radio Shack and "just mount it on top." The preamp was so thin regular pots would not fit. The shame is that the amps were truly special. As far as I am concerned Dan can go shovel sh-t in a corner.