With the 6XX offer out of the way, this comes back into the picture for those looking for a dry, neutral sound, solid timbre, and great soundstage and imaging. I believe this is an all-time low too. If you like Sennheiser mids and timbre, you may be slightly off-put by this headphone, but it's a good all-rounder.
You'll need an amp for the best sound (control in the bass, extension in the highs), and these will EQ about as well as anything on the market due to very low distortion characteristics.
Check past deals for lots of comparisons and comments. Enjoy!
373 or these? This puts them around the same price on special from the same seller