Ayre DAC vs Auralic vs Metrum vs Bel Canto

Haven't heard the Auralic or Bel Canto but can rightly say the Metrum Octave outperformed the Ayre QB-9 in my system (Shindo based).

You will get better feedback if you tell people how you intend to use them: fed from a computer (PC/Apple?) from a sound card, USB-to-S/PDIF converter, connected to what equipment, and if you are interested in hi rez. Ayre only has USB in, so you are likely thinking a computer, but Metrum only has coax and optical in...so you are likely thinking something in between computer and DAC. Not convenient for you making people providing feedback guess what you are thinking, I guess.

A LINN DS would be a better sounding piece. I think the QB-9 is USB only?

Which LINN DS would be better than all of these, and is it in the same price range?

Regarding the use, I was thinking of using USB from a computer with Amarra or something like that. I would be buying a converter if I got the Metrum.

I'm thinking of a Mac. Also, right now I have focal studio monitors amped. I don't yet have a pre-amp to power this DAC.