I own my own home studio and have been using this model of headphones plugged into my Alesis Firewire mixer (part of the Evolution range) for about 4 years now. They are lightweight and faily robust. As for comfort levels the pads are very good, not too pressurized on the ears and I can sit here fore several hours quite comfortably with them on without too much discomfort, anything after 4 hours becomes a little painful.
With regards to the all important sound quality, again they are fabulous. The bass is frequencies are good and it represents both gengers well when you are monitoring vocals. Distortion is minimal, mids are good and well in your face and high range sounds crystally bright. But of course soundshaping and details is only good as a mastered track.
I would say that they are good value for money and ideal for anyone trying to monitor with them as a newbee start out - not for the pro I may add. Personally I would never master a track solely with them. Great for amateur DJing, sticking them through an iPad or iPod etc where sound detail isn't a primary factor. I also use them for monitoring live sound through my Zoom H1 recorder and they are perfect for this.
They must be good as I have gone through 2 pairs now (my son broked the first pair) - I don't usually repeat purchase on electrical goods!
I have owned these headphones for several years now, and they have served me well. Nevertheless, they have never been entirely satisfactory, and I'm not convinced how well made they are.
First, the good points...
Generally, the sound quality is excellent. They fit very snuggly onto the head, and provide a completely soundproofed environment for the listener. This really is excellent, as with many headphones, you can still hear a great deal of external noise when listening. They can be adjusted, although only the height can be altered. Nevertheless, they do stretch, so I suspect they easily fit to any head shape.
...and the bad points...
Firstly, the mini-jack on the end is rather poorly fitted. In all appliances and devices I've used the headphones with, I've had to spend a few minutes twisting and turning the mini-jack in the slot, in order to get sound coming through to both the left and right earpiece. This is incredibly annoying! At first, I thought it was the device itself, but actually, having tried several, it's the headphones. Also, occasionally, you can be listening, and the sound will drop out of one ear, and so they mini-jack as to be adjusted once more. It's almost like a sort of macabre fitness device...after a few minutes, you have to jump up again to adjust it!
Each earpiece has a separate connection, and like the aforementioned, these tend to just slip out easily. It means that when using the headphones, a lot time is wasted checking all these connections, in order that one gets the best sound quality possible through to both ears at the same time!
The cable is very long, and probably too long for most people's needs.
In the past, I've always found Stennheiser to be an excellent make - indeed, the sound quality is superb - however, they have been let down by the quality of design and manufacturer with this product.