I have a pair of P3s, which I love. I really wanted to own the P7s, but after bringing them home from the Apple Store and trying them out they were just too uncomfortable. About 5 min in they left a dull pain on the top of my skull, and 15 min in I had a splitting headache .
It's a damn shame too, they sounded pretty sweet from what I heard. I ended up exchanging for a pair of Sennheiser Momentums, which I am enjoying immensely. Also picked up a E12 Mont Blanc and it works decently with the Senns, despite their low impedance to begin with. Provides just enough sub-bass to make the Momentums sound richer down low, eliminating probably the only "weakness" in the Momentums. (nothing beats the vPulse + amp for bass though, imo)
Anyway I hope you enjoy your P7s when you get them. I'm extremely jealous, they just didn't work out for my melon.
Oh man that is such a shame! I'm slightly worried whether that might happen to me! Theres always the chance, not the makers fault, we all just hear differently/feel comfort differently and most importantly, all have different sized heads!
Thanks for the info though man, enjoy the Momentums!