Sennheiser HD 660 S vs HD650 vs HD6XX

Time for everyone's favorite topic of discussion; I've seen many posts about this on reddit and other audiophile sites that seem to contradict each other depending on when they were posted but what I've gathered so far is that all 3 of these headphones have just about the same sound quality with some minor differences in treble.

The 650 and 660 S are on sale on amazon for 350 and 300 and since my hyperx cloud 2 headset just died I figured it'd be the perfect time for an upgrade; I'd love to hear any and all opinions regarding these or other headphones you recommend around this price point