I've been wearing the P5s almost permanently for several days now, and I've yet to find them uncomfortable. Furthermore, I've had no problems with overheating despite the closed-back design and the large amount of leather pressing on my ears - an issue I've had with other headphones. Yes, Teufel AC 9050 PH, I'm talking about you.
Particularly inspired is the decision to make the ear cups detachable, held in place magnetically on small nibs. Should you damage one, or simply wear it out from over-use, you'll only have to replace the cup itself - a cheaper proposition than buying a new pair of headphones.
Removing these cups also reveals another trick of the B&W P5 headphones. Under the right-hand cup you'll find a serial number, which isn't exactly exciting. Under the left-hand cup, however, is a 2.5mm jack, into which the headphones' cable plugs. Two cables are provided with the P5 headphones. One has, as you'd expect, an in-line remote for use with your iPhone, iPod or even a Mac for that matter, with the second, predictably, eschewing any controls.
This might seem like an unnecessary addition, but it's indicative of the thought that's been put into creating these headphones. Plus, some MP3 players won't work with headphones that also have a microphone built-in, with which the remote-less cable should work. So there!
As with so many recent Apple-orientated products the remote will only work fully with newer devices. As such, while the volume and play/pause control worked with my iPhone 3G, the microphone did not. I was able to use it to deliver Voice Control commands to my 64GB iPod touch, although why I would want to, except in the interests of testing, I cannot fathom.
It's also worth mentioning that the cabling is quite thin, and feels by far the weakest point in the P5's design. It's not going to fall apart in your hands, but it does seem something of a let down when the attention to detail is so good in every other respect. There's even a 3.5mm to 6.25mm adaptor thrown in, alongside a fabric carrying case, to round out the overall package.