Even if the Sennheiser HD800 where the same price as I paid for my HD650,
I would not buy them,
because when I tried them,
I found that the were too big (Ear cup) and not comfortable,
however, the sound was better than my HD650,
normal at three times the price...
By the way:
If I did not know what to do with my cash, meaning I had lots to spare,
I would not hesitate and go for the top of the line STAX.
I had a pair 35 years ago and today I am still kicking my butt for selling them.