Just saw your post.. ironic since I came here to post some praise for the Mytek. Not sure if I can offer much objective help at this point though.
I picked up the Mytek recently from the yardsale here and love it except for the sleep deprivation it seems to cause whenever I turn it on late at night. I'm hearing details and image depth I was missing previously and feel like it can help me feel confident and decisive in making certain audio manipulation choices. I've only run it with Senn HD650 cans so far and have not yet used it to feed the speaker system. The 'air' and 'image depth and space' of the top end are two aspects that I really like about it and a large portion of the comparitive improvement it's provided me. Those aspects are also what I hear improvment in by switching on the DAC's superclock feature instead of clocking to the incoming SPDIF stream (24 bit out of a Musiland USB>SPIDF converter). Maybe I'm hearing a reduction in jitter?
I have not compared the Mytek directly to the other DACs you mention, though I plan to do so with the Benchmark DAC1 which another TS member in town has. So I can't back anything up from actual comparative listening, but my impression is that the Mytek may be perceived as slighty 'brighter' up top than the Lavary or Benchmark. That impression arises collectively from what I've read, what others have told me, and from listening to the ADC>DAC loop comparisions a few years ago that are posted on the Mytek site. I tend to weigh clean, clear, open transparency heavily in my personal hierarchy of sound preference, so that's a good match for me and I'm very pleased so far in the listening I've done, which has been primarily for enjoyment.
A more objective comparison awaits.