I bought a pair of ATH-M40x a long time ago and since stopped using headphones until recently. After buying a pair of Bowers & Wilkins Px7 S2, which are top quality, I started looking for a pair of open-back wired headphones and came across the ATH-R50x.
These are incredibly good value for what you get; well made, comfortable, lightweight and very good regarding sound quality. There's something I prefer about just plugging in a pair of headphones and not having to worry about the battery level!
A pair of Beyerdynamic DT 900 Pro X's is now on my wish-list but I'll enjoy these in the meantime. Recommended.