@hifikenobi - I did check out your system and it is wonderful - thanks for posting it!
Like you, I also find the differences in DACs not subtle. I recently added an Aries Cerat Helene DAC to my system and, after finally getting it dialed in, I find the sound to be compellingly natural/organic with a mix of clarity, sweetness, bloom, dynamics, and rich tonal qualities that come together in a very convincing manner. I currently have five other DACs here and can easily pick out the differences between them.