It's been a long time since I've used an on-the-ear headphone anywhere outside the home (I switch between sound-canceling Audio-Technica cans and Fidelio L1's for music and gaming). But these B&W P3 headphones surprised me, hitting a pleasant note between performance and size, with long-wear comfort (notably the super comfortable fabric covered pads), a foldable travel-friendly form factor, cell phone mic compatibility, and most importantly sound performance.
When comparing and contrasting, the P3's left my usual in-ear earbuds sounding muddy in comparison, with an equal dose of warmth and clarity normally lost when I put on a portable pair. These models are notably not sound-isolating, so if your commute is hampered by loud traffic and intrusive ambient sounds, or if you work in a raucous workspace, you're better suited to larger models with more active sound-canceling technology.
But I find myself turning to the P3 more often and my earbuds less and less when looking for a pair of headphones to easily throw into the backpack or travel case when I know I'll be on-the-go and want to listen to music for hours and also occasionally jump into a conference call, convinced these headphones strike a balance between portability and comfort, without looking ridiculously conspicuous like my larger at-home headphones.
And of course, just like everything else B&W puts out, the design, feel, and finish match (maybe even exceeds) the quality of sound, right down to the modern and protective carrying case.