The Metrum Acoustics DACs are R2R non-oversampling DACs and although that is not a new way of doing things, Metrum were somewhat early to visibly market that format when, at the time, a primary goal of DAC designers was to make a DAC that didn't sound "digital." Their designer, Cees Ruijtenberg, used paralleled industrial DACs and their early model Octave received a bunch of reviews in 2011/2012. They kept upping the number of DACs used in their models and the sound kept getting better and then they began using DACs that Cees designed and that the company (All-Engineering) manufactured in-house. They spent good effort on the power supply to keep noise low in their DACs and boasted very high S/N ratios. Their latest innovation was an internal volume control that did not throw away bits but rather adjusted the reference voltage, thereby not affecting the quality of the sound. They also designed and manufactured an amplifier.
A few years ago, Cees left Metrum over business disagreements with ownership and started a company called Sonnet Digital Audio, which has a couple of well-regarded DACs on the market currently. Metrum Acoustics, the company, went through an iffy period where customers were not sure whether the doors would stay open or not. Cees (who was always excellent to work with) offered to repair equipment for his former Metrum customers and those who tried to reach a human being at Metrum, including myself, were mostly frustrated. At this time, Metrum Acoustics seem to be still in business as there is a website where they are selling products.
Regarding the products, I have owned their Adagio, Pavane, Jade and Hex DACs, and their Ambre and Baby Ambre endpoints. I still own and use the Jade, Ambre, and Baby Ambre. I have never had any problem functionally or sonically with any of their products, so have never needed service and would say the products are well-constructed. My favorite sound was from the Pavane and the Adagio was close. IMO, the sonic signature is organic and natural, while being rather "clean" sounding and maybe leaning more toward detail than a tonally full sound, if that makes sense.
Do your research as there are many other R2R style DACs available that also offer their own organic, natural sound. Two companies that come to mind are Sonnet Digital Audio and Mojo Audio.