It'd be great if you get a chance to test some more high-performance DAC HATs along the vein of the ALLO and ApplePi units. We've now seen the broken, the low end, the cheap but cheerful (HifiBerry), and the very top end... is there anything else better? or close? to the top end?
Again, it's great to see DAC HATs reviewed - aside from just a few manufacturers that provide their own data, there is absolutely no way to know the implementation is so craptacular as the Aoide unit, without someone hooking it up an looking.