[Rightclick/Scissors]

Looking for flat response, detail, not colored, not fatiguing, balance, good stereo field, durability, comfort, etc
 
As far as I'm concerned, the M50's have it over their rivals in most of these categories, and their overall score makes them a world-class contender in this category: studio work. I've owned my last pair for nearly 4 years and they're only just starting to wear.
 
It's time for a new set, though. Figured it might be cool to get something different and keep the M50s for reference.
 
Have read a bit about the Q701s and Senn HD 650s. Both sound promising. Anybody got experience of a direct comparison?
 
Any other models to throw on the maybe list before making the call?

 

[NA Blur]

The HD-650 is finicky and I suggest avoiding it unless you can demo a pair for a few days.  The Q701 is decent enough, but for me the K550 sound better is less bright making it easier to listen to hours at a time.

 

[irishsammy]

When I read all the descriptors you put up, the first thing that pops into my head (minus durability because I haven't had my pair long enough to know how it is in that respect) is the HD600.  I've heard that it doesn't sound much different than the 650 but that's my gut reaction...