Best High End Audio Manufacturer???

Magnapan.

This revolutionary loudspeaker company has been around since about 1970. It was revolutionary because its speakers it did not use cones or electrostatics. Instead it uses a planar driver. Every model introduced over the years was affordable, and preserved the music. Their 3 most popular models, the 1.7, 3.7 and 20.7 are arguably best buys in their respective classes. I just love how this company quietly improve its products over time without losing focus.

FM Acoustics.

ARC might have the deepest roots and MBL might have the wow! factor, but I'd be inclined to go with a company like Magnepan, Vandersteen or Rega. They still offer excellent products at real world prices. The MMG, Vandy 2, and RB 300 are the most impressive high end products out there for me.

Pass Labs deserves to be in the discussion.

Best in the sense of quality versus cost and in personal integrity, Keith Herron is hard to top. If record care products count, Walter Davies of The Last Factory is another person and product of unusually high quality. If these two examples are of too recent a vintage to be eligible, it's gotta be Peter Walker and the original Quad ESL loudspeaker.