I can find the HD650 on amazon for for ~400 dollars and the HD700 on Sennheiser's outlet store for 500. I listen to mostly country and 70s/80s rock with a little bit of more popular mild hiphop/rap on occasion. I could get the 650s on the outlet store too for ~330$ but you apparently can't...

I've had these headphones for ~ 9 months and I am now considering upgrading to either the Sennheiser HD600 or 650. I like the sound signature of the M50 for the most part and am wondering which of these I might like more. I don't have a way to test these out for myself unfortunately.. (Open to...