Most underrated Audio Manufacturers

Most Ortofon phono cartridges, and especially in the lower price point models, for the fact that they have historically had excellent positional tolerances from the stylus (when loaded VTF) to the cartridge mounting surface. Allowing for good azimuth and SRA results even with rudimentary set-up methods (horizontal tonearm and accurate VTF) applied. And musically they have offered a wide selection over the years at very good prices with exceptional performance. 

Very good point r f  !

Thoress preamp and phono stage and TW Acustic phono stage.

Among SS amplifier builders, I would say Coda is pretty underrated. They've gotten some reviews over the years, but not nearly as many as some other, much more high-profile manufacturers. They seem to do their own thing (including OEM work) and if reviews come their way, that's cool--and if not, that's fine too.

I've heard or owned a decent number of Coda amps over the years, and they keep getting better. They're not the fanciest or most strikingly impressive, but they make music in a whole-cloth, highly transparent, and effortlessly dynamic sort of way that I find compelling. In short, they just sound RIGHT to me. They've been in the game for quite a while now and clearly know what they're doing. Anyway, just one man's opinion.

I really like croft's little integrated amp and they have a good phono stage. Understated but outstanding sound for the price.