if they have balanced armature design, they will hiss. the better the phone, the more the hiss on a powerfully dirty amplifier. my um2 (very good phones as well as e500 hissed greatly on poor amplifiers).
Aren't these released on the 17th? So no1 could know.
Anyway, I was thinking of buying them too if the sound is comparable to the SE210. Else I'll rather get the SE210 for just 50 bucks more.