PS Audio Direct Stream Mk2 DAC - How good is it vs Mk1? Weiss, Bricasti?

I have the original PS Audio Direct Stream DAC, and had been considering upgrading, as it is the oldest item in my system, and I am getting the itch to upgrade.   I had been looking into the Weiss 501 or the Bricasti M1, used.  But have ready several positive things about the PS Audio Mk2.

I am wondering if anyone has really compared the original to the MK2? Or to the Weiss or Bricasti?

thanks!