I had one of these for a short while and was rather unimpressed. I found that it only slightly outperformed a jolida jd 1501a i had at the time. I replaced the panache with an aragon 4004 mkII and anthem pre 1l that trounced the panache in every way (equipment at the time was eminent tech lft-viiia, pioneer dv-45a, monarchy m22c dac + dip upsampler). I will say that the headphone out on the panache sounded wonderful with my hd600s.
Portal does have great customer service, however. I bought the amp used (not a demo from portal but from an individual on audiogon), and it arrived with an intermittently functioning headphone out. I sent it in for repairs, and they fixed it no questions asked.