DAC - USB2 experience in Linn - KEF system?

I want to retain the soundstage and dynamic range I get today but get the convenience of FLAC with the addition of a DAC. I listen to Jazz, Rock, Trance, and Classical.

I currently have Arcam CD72 source to Linn preamp and 3 Linn amps triwired to KEF reference towers. Now I'm looking to add FLAC as a source and looking for the right DAC. The DAC should support USB2 out of my MacBook Pro and I will optionally use CD as transport via optical out if the DAC offers an improvement over internal CD electronics.

The range of DACs I have researched include:
-Audiophilleo1 w/PurePower w DSD128
-Arcam rDAC
-PS Audio NuWave
-Micromega MyDAC
-Schiit Bifrost w uber Analog
-Wavelength Brick
-Woo Audio WDS1

I'm looking for DAC comments from people who have Linn or similar sounding systems. I find it so hard to find a way to do live comparisons so any feedback is appreciated. Thanks!