Quibbles aside, the Audio-Technica ATH-M50x headphones are a modestly improved version of the already spectacular model they're based on, and among the best-sounding pairs you'll find for less than $200.
The Audio-Technica ATH-M50x Professional Studio Monitor Headphones offer excellent build quality and very detailed, balanced sound with tight bass; They're also very comfortable and have slightly more cushiony earcups along with a detachable-cord design (three cords are included).
There's no integrated microphone for making cell phone calls and the bulkier design makes them less suitable for mobile use.