"Ok, suppose that I rule out the JVC DX3"
Why? Did I miss something? Why are you ruling them out?
As for how they perform with portable equipment I wouldn't know, as I never use portable equipment. I can say this though: The DX1 is an exceptionally neutral and uncoloured product, so I would not attempt to use it with anything not similarly neutral and uncoloured. I get fine results with the Marantz 4000, but of course would expect better results with a better amp so long as the characteristics of said amp were sympathetic--ie, the DX1 needs a warm sounding amp; cold and analytical is out.
Regarding microphony, the DX1 like the DX3 has rubber cups fitted to the ear cups presumably for damping. If so they don't work, though they may have some other function. Microphony in a closed back phone is very difficult to eliminate as vibration essentially has nowhere to go. As stated, I solved the problem somewhat, as well as eliminating mechanical noise from the swivelling joint, by covering the whole back of the cups with Gaffa tape. Since this is black, it actually looks OK, but it means pre-positioning the cups to your head shape since they're obviously going to be immoveable after the tape is applied and won't fit anyone else. If this sounds like a lot of trouble it is, but I couldn't have lived with all that creaking every time I moved my head---those into heavy metal obviously won't be as bothered. I'd like some feedback on this from anyone with a pair of either phones.