I was looking for phones that would pack plenty of punch without sacrificing any of the qualities of their full-grown, ostentatious siblings. Anyone who's even moderately serious about headphones knows that the smallest improvements come at a price. In the case of these phones, the cost is easily justified. I've compared them with several portables in the $5-10 range along with some full-sized models weighing in at $50-100. Conclusion: these are worthy of being your "front-line," and perhaps only, pair of phones. They're up to the task of distinguishing each of the instruments in a jazz rhythm section or reproducing the spacious quality of an entire string section. The treble is distinct and "alive"; the bass is, if anything, more than I require (and the PX 200's are supposedly the bass-heavy models). Comfort? They feel the same as any $2 pair of portable headphones--until the music begins, at which point "wearability" is not even an issue.
Be forwarned that no 1/4" adapter is included. Apparently Sennheiser wants consumers to view these as strictly low-end phones suitable only for connection to a portable CD player. Nonsense. My only real disappointment thus far is the awkwardness of folding and fitting the headphones back into their hard case. If I can get this down to 60 seconds or under, I'll probably revise my rating upward.