Agree with everything you've said :)
It also depends on what you're listening for, detail, tone, realism, everyone has their own preference sound. Most Massdrop users are headphoners, when I listen to my headphones I am concentrating more on the detail and soundstage, and less on the presentation and realism (vs my speakers).
When I listen to my headphones, even comparing my el cheapo FiiO against my $2k DAC, I am hard pressed to find any differences in detail retrieval, but the presentation is completely different. I've got a custom built DAC that is $5k in parts alone, it makes zero difference on my headphone setup, but worlds of difference when paired with my speakers.