I agree and am happy with mine, I've many great headphones (Sennheiser HD595's, 600's, Grado HF-1's, MS-2i's, and RS-1's). The P5's are a little expensive for what they are but they are great within their own nitch. I toss them in a bag and use them for travel, in bed, and when walking the dog right out of my un-amped device.
The P5's are a great isolating portable/mobile "full-sized" headphone option to go straight into your device. I compared them to some other smaller/foldable closed back options (cheaper stuff in the 100-150 range) and the P-5's were clearly on a slightly more refined/detailed level).
I think the key thing you have to be open to is that you are paying for design/development/marketing/materials so its hard for the P5 to stand up against a $250-$300 headphone that has been built for many years and is simply molded plastic.
I'd say the sound quality value vs cost starts to cap out at about $200, after that you are paying for the look/aesthetics/comfort (if its there for you). For me I do not mind, I like the headphones and would rather pay $50-$75 more for anything to be built of this quality rather than cheap plastic. Actually I would rather pay 20-25% more for a lot of things to have them look and feel like the P-5's.
With regard to Bose comparisons, I think its obvious B&W is trying to go after that prosumer/apple big box "higher end" retail market and a lot of parallels are obvious in product placement/marketing/etc. I think though that B&W actually makes products on par with their prosumer marketing. They are a little pricey but you get what you get. A lot of Bose stuff can actually be among the most expensive and hyped for the non-discerning listener.