The PX 200 II sound very very nice, but provide no isolation. So I don't think you'd like them on the bus or other noisy environments.
I have the HD439, mentioned above and they give medium to good isolation (not as good as my ATH M50s for example) and are exceedingly comfortable on my ears.
I thought the top end to be a bit rolled off at first, but has opened up with use. I think the mids are quite well integrated with the bass, and the bass is entirely sufficient for my listening. For a closed headphone, they give a fairly good spatial image (much better than the M50's for example).
I did listen to the HD 429 at the store, but set up was far from ideal. Maybe more clarity -- but rather suspect that they just didn't have same level of mid and low bass. Guessing.