Listening to them with Brainwavz HM5 pleather pads right now. So far i really like their sound. They are crazy fast and i have no idea how some people think the bass is too much on the T20RP's. For me the bass is just right. It doesn't overpower the mids and i mean it's planar bass so it's really good. The main problem is some buzz on the right driver with some bass frequencies so i have to order a second pair. I guess that is alright considering their price. Insane, just insane. Looking forward to burning them in.
EDIT: Someone asked for a comparison to the MT220's. Its a bit early but the mids are more forward or less recessed on the T20RP's. The bass is way less bloomy and tight. As said, it's planar bass.
The highs are sparkly with the HM5 pads but on stock they are tamed. The highs on the MT220's were a bit too much for my liking but YMMV. All in all i certainly prefer them over the MT220's.
Look at these two frequency responses:
T20RP
http://www.innerfidelity.com/images/FostexT20RPMk3.pdf
Fidelio X2
http://www.innerfidelity.com/images/PhilipsFidelioX2.pdf
Don't these two look pretty similar or am i crazy? From memory the bass on the T20RP has the same quantity as on the X2's but doesn't extend that deep.
EDIT2: Is there a known mod yet to fix the bass roll off? I am not even sure but i think the HM5 pads already bring out the sub bass a bit more.
EDIT3: After about 4 hours listening i have to say i am in love. Maybe i'm a bit of a basshead but the bass from these is just addicting. The highs can become a bit sibilant but i heard its "worse" on the T50RP and T40RP so the T20RP is the perfect match for me. After listening to alot of Twenty One Pilots the speed of these becomes obvious. I think i can't go back to dynamic drivers now because planar magnetic is just sorcery.
EDIT4: Glamour shot!
EDIT5:
A better view of the two FR from the T20RP and Fidelio X2
Left T20RP, Right Fidelio X2