Summary: These sound great, and fit great in my ears since most earbuds won't stay at all. Volume control and play button are great, but take some getting used to since they're pretty much flush. The wires are thin so I have some worries about their durability, but that also means they don't make noise. The right earbud wire is longer than the left, to go around your head. That can be good or bad, but not a big deal.
Pros: Comfortable, Good Sound, Good Volume Control, Lightweight
Excerpt: Great set of noise cancelling earphones. Great sound but to get the right sound from your iPhone 4s for your own particular taste, u do have to try each different equaliser setting to get the right sound. Downside for these earphones is the thin cable. It feels & looks flimsy compared to other Sennheiser models. Also the J cord is a slight pain, uncomfortable to wrap around your neck and the plug is a straight fit and not L shaped for better protection.
Excerpt: these are shocking! well the sound is great like the rest of the sennheisers, but the jacks straight plug in design is a real step back from their L shape ones on the cx300II s I upgraded to these at the advice of the accessories guy, and although i do love the inline controls and the sound quality (i didn't notice a huge difference tbo) I've had to replace 2 pairs of them in the last 6 months due to the jack casing splitting and a faulty earpiece...
Excerpt: I'm a sound technician by trade so when it comes to audio I'm very hard to please for the last 18 months I've owned a set of the MM50's and loved them and slowly saw that they where dying off which meant the moment I had some spare money I was buying a new set, I went to the local to replace the MM50's instead I upgraded.