Pros: Good sound with a strong bass. I really like so called Open-Aire acoustic system. This is my favorite Headphone at a moment. I paid only $40 during Black Friday sale and can say that the sound worth every penny I spent on it.
Cons: I wouldn't pay the full price, despite the sound quality. I was very careful with these phones and never moved them away from my desk; used not more than for 50 hours total. Tonight the left driver suddenly died in the middle of song. Had to disassemble the left side and to solder wire which simply fell off from a little PCB. This wire goes from PCB to speaker and should never be under any stress, except a vibration. Soldering quality is just ridiculous. That's why I ...
Cons: Bad distortion on songs I've never had an issue with. Mainly distorts the vocals/treble. Even the cheap earbuds that came with my ipod/phone don't distort like these Sennheiser 239's do at higher volumes.
Summary: Does not stay on the head well so do not plan on doing much while they are on. Just sit tight in a quiet place (open phones) and enjoy the music.
Pros: Great clarity
Cons: VERY uncomfortable. The earpieces are small (about size of the ear) and rests solely on the earlobe. If you are not used to headphones pressing on the edges of your earlobes, you'd best stay away from this. It hurts after a while. I tolerated them on for an hour before it became unbearable.
Pros: Know the Sennheiser name. Have them for home. Love the sound. Comfortable. Well made. Stable during wear. Good price, received addl off (limited time). Even without the addl off, the retail price in my opinion is fair. I would love to hear through a studio model, I'm sure I won't be disappointed when I get the chance.
Cons: Do not fold, limited color (just black). But these things are easily sacrificed for the sound that Sennheiser provides.