P7s suffer from style.... If they looked uglier then people would OOh and AAh about how good they sound but they happen to look brilliant, so therefore its difficult to get Style over substance out of your head.
For me after testing a whole load of headphones the P7 stand head over shoulders above anything else that you can get in terms of Beats, B&O (although with a bit more Bass, the B&Os would be incredible.. they are sooo comfortable), many of the sennheisers, Parrots, and other manufacturers. Sure there is the odd one that will be more transparent or have a wider soundstage etc. for the price, but to make the P7's unlistenable.... I think this would only affect 0.5% of global headphone listeners. you would need to have some serious listening sensitivity and spend long hours listening to them. I also believe that P7 offers this level of sound WITH the superior packaging/style so it just depends if you want something pretty with excellent sound or something less pretty with the slightest of better strengths...
as i say unless you have superior listening sensitivity, you dont have to bother.
I personally cant believe how good the P7s are, hearing new things in songs every time i listen. And i dont use a headphone amp... yet... although my Intergrated Amp does have a headphone amp but i dont notice a difference between it and playing direct from iphone.