I prefer open headphones over closed :)
I've tried them with and without an dedicated amp (Matrix M-stage) and I've found that they require an amp to give the best.
My iBasso DX50 seems to be good and strong enough to drive them properly, maybe not at the best, but quite good.
I've got a decent volume with maximum gain and volume from 230 to 250 depending on the track.
I've bought these manly for rock and metal and I've tried them wiht these genres first. I'm really satisfied by the overall sound quality of these. Definitely onother level from my HD598 and I think these are PEFECT for the genres mentioned above. The sound is accurate, balanced, worm but natural (not colored at all). I love all of these: the mids are bright, the hight are clear, slighty veiled only at the first listening but then well balanced, the bass are... well AMAZING! I didn't expected so much bass impact and extension, expecially from an open headphone.
I think all my next headphones (maybe because these are what I was looking for!) will be magnetoplanar :D
Well.. I know they are warm.. but I also think that "overall" the sound is someway "Neutral", the bass is not overwhelming the other frequencies!
For the others new models I've read something :)