I've owned the XB700s previously and I can safely say the old XB series is so much better than the new crap. These new ones have shocking build, bad fit and underwhelming sound. It seems like Sony wants to jump on the mainstream bandwagon at the risk of losing its niche(us) audience. That's understandable, as there's more money it it for them.
Regarding the Sony cans debate as a whole, I've owned numerous Sony cans and IEMs, and I have to say we are now facing the end of an era. Not just with the XB series but their lineup as a whole. Build quality seems to be taking a back seat(MDR 1R jack rattle, anyone?) and sound seems to be more mainstream-ized and mediocre. That being said people shouldn't judge Sony on the quality of their current cans, some of the stuff they made before was legendary(V6, MA900, even the fabled Qalia).