Optical s/pdif isn't without it's problems and many would say it's much more jitter prone than USB whereas USB runs into problems on the receiving end if there is a lot of noise and it amps up the processing ... Schiit clearly seems to be going the USB route, choosing to clean up the USB and then outputs to coax s/pdif in the Eitr and recently adding in its Gen 5 USB. There's also rumors they're working on their own USB chipset to handle the processing load.
I started out using optical on the mojo out of my MacBook but have switched to USB as I notice no difference in light A/B testing and USB is just much more convenient. As for the Hugo, I just don't get the argument for it when you could buy endgame DAC & tube amp for the same price or multiple of them (e.g. woo audio WA2 and schiit gumby) or if you need transportable you could get woo WA8 and new set of nice headphones. But the heart wants what it wants.
Well Chord DACs are immune to jitter, as the samples are re-clocked inside the DAC at the correct sampling frequency. Therefor making optical the most likely to be most accurate, if file storage device is noise free.
I am exploring USB clean up, of the power lines. I think I am going to get a JitterBug, or WYRD. If it improves the signal even slightly, it will be worth it. The Chord Mojo is stunning, and I know it's signature well on USB, so I should spot any improvement. I think the noticeable gains are more solidity, and a bit more clarity. ..........
In the case of optical. I think it will be a matter of getting the signal through a device which creates the optical signal. One that doesn't suffer USB noise. I am actually thinking it might be best to get a sound card that specialises in being shielded. Or put a JitterBug or WYRD on an external USB to optical converter.
(There is a very strong argument for getting rid of noise. If it's the case that it messes up the signal processing or samples. I guess it only takes one bit (of a byte/packet/sample) to be off, and one sample is lost. ... I was recently doing some work in Cubase. I discovered that changing one sample point even fractionally was noticeable, if you knew previously how it should sound. .. Anyway that's all for another thread.)
I don't agree that for me, about what you said, about value for money spending. Or that there is an end game DAC and amplifier worth buying at the price range you suggest. Of Chord Hugo £1,400, or Hugo 2 £1,800. Maybe in the world of headphone amplifiers, but not in the world of regular hi-fi amplifiers. A headphone amplifier would be useless to me, as I only use headphones part of the time. Then when I use headphones I plug them into the DAC. Waste of money buying a headphone amplifier then, since you gain nothing from using one. The further you travel from DAC to headphones, the more signal you lose. If you are happy with Chord DAC, you use that.
In terms of DAC cost alone, the Hugo TT was widely regarded as setting the standard at its price, when reviewed at £3,000. Yet some feel the Hugo 2 outperforms the Hugo TT. I guess either DAC would make someone happy, but neither are acknowledged as end game. They are close enough, to be extremely happy to live with though, and 'feel end-game' though . However not end game, since everyone is aware of the Chord DAVE anyway.