Here's a quote from you about the ZX700: "i listened to these at the sony store and didn't like them. they sounded bad. everything sounded out of place, it was harsh and also boring." Then in another thread you say(paraphrasing) the M50s are "good" but not as good as the 840s. Make up your mind man! j/k
Anyway, simple answer is the price went up. Still $125 on Amazon which is good.
That was a 3 minutes audition. I have had more time with them.