Been privately conversing with a member here who's exclusively using I2S input on 006, has no usb capability. And since LAIV Harmony purchase planned on going I2S, I have Denafrips Gaia and two different I2S specific (no video capability) cables coming in, one all copper, the other Tubulus Concentus pure silver.
I don't recall ever seeing a 005 review using optimized I2S input so this intrigues me with 006. Going I2S, adding a component and cable, but eliminating usb to I2S conversion within dac, trade offs? 006, as well as Harmony offer sync or async modes which means using host clock or local/dac clock, Gaia clock is reportedly one of the best OXCO out there, good test for quality of 006 clock. Probably a month or so out with burn in/ waiting on Tubulus cable build to get good read on preferred input.