Andre @allo.com kindly sent a sample of the DigiOne board for testing with my Pi’s. It has been playing in my main system for a few days now – time for some (early) impressions. 
- It sounds really detailed / fine-grained
- Nice definition in the lower regions
- Highs are silky smooth – no trace of digital edges
- Compared to the Hifiberry Digi+, it has a bit more sparkle (or: the Digi+ is slightly flatter)
- Compared to a Bluesound Node 2, the Node has a bit more body but is also a bit more compressed; the DigiOne is a trifle airier and more extended
My system consists of a pair of Meridian DSP5200 speakers (2x SPDIF) with Blue Jeans cabling and a MiniDSP/Dirac room correction box added in for good measure, all fed by a Pi3/DigiOne with Aqvox LPSU.
I know, lots of bits and slights and trifles, but remember we’re not landing a man on the moon here: it is ‘just’ a digital transport. Do everything right though and you’ll end up with remarkable results: exactly what Allo appear to have achieved here.
Now please excuse me while I’m off to some more music. 