Ayre DAC vs Auralic vs Metrum vs Bel Canto

You wouldn't be disappointed with the Ayre.

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.