I bought these headphones after having great experience with an old pair of neckband headphones from Sony about 5 years ago. Things can only get better, right?
Wrong, in short. I bought these headphones and was really not too happy with the overall 'hugeness' of the sound, of lack thereof. I rummaged around and dug out my old Sony MDR-G52's, and eventhough they're now lacking in ear cushioning foam, they sound far, far superior to this Sennheiser unit. The construction on the Sony headphones is still plastic, but more solid feeling. The earpieces also slightly heavier and thicker, hinting at the presence of bigger drivers, and when it comes to any speaker of any size, that's generally a good sign.
Sennheiser bass response is lacking, and they slightly pull away from the ears, leading to a lot of sound spill. As a whole, I don't have much good to say about them compared to my 6 or 7 year old Sony headpones. Even the jack is not of a high quality. As a first time Sennheiser customer, I expected more. Also worthy of note, these Sennheiser headphones can't handle an iPod on full volume without distorting.
I'll be trying to buy a new equivalent pair of Sony neckband headphones in the very near future and returning this Sennheiser pair.