dCS Vivaldi - the complete system is the DAC ($35K), Upsampler ($22K), and Master Clock ($15K), is that right? Plus Transport ($42K) if you want to play CD/SACD?
The HD DAC X retails for $65K, so in the ballpark of the Vivaldi. A direct comparison would be interesting!
For me personally, I like how Nagra solves problems and builds their components, I love the Tube DAC sound, and the company has outstanding customer service. I also love the aesthetics, so I have no interest in dCS. I also have no room for 3 boxes...
I use a Taiko Extreme, so I have no need for the streaming/transport side of the equation, since the Extreme has no equal today.