The FP and the MX2 in the dac section I don't feel are too different in sound. It is both of their amp section that makes a big difference. I threw in a dual opa LT1028 in the fire phoenix that gives a real nice dimensionality to it. It expands the sound of the CS498.
Seems to me the dac end of the MX2 using the PCM1796 is a newer version of the PCM1794 which is a nice standard DAC chip. . It has a very nice clean sound to it much like the CS4398 chips I can confirm the DAC in my ME is superior out of all my units. But it is more the OPA2227 and OPA2134 used in the amp portion that acts kinda like the LT1028 does for my FP.. The sound combo is very nicely done.. These guys clearly know their sound using this combo..
If your looking for a nice high end portable DAC. to use with your amp. Look into the HRT microstreamer. Seems to be just as good or better than the ME but cost $100 less.
Thanks for giving me your impressions. I am really quite satisfied with the FP's DAC for now. So for the time being I will enjoy my FP until something else comes alone that is significantly better for a bargain price. And I am sure I will read about here on Discovery first! :)