https://www.youtube.com/watch?v=3rUndzpdo1I
Not really a fan of linus but he shows some stuff, you can skip past some of the waffle.
Default test the 1800x beats the 6900k comfortably in Cinebench at half the price, 1700 destroys the 6800k while $100 lower (without factoring in cheaper mobo), etc.
What will be most interesting now is overclocking and, he said X chips should overclock better but I'm not convinced, he shows at the end with BF1 comparison the 1700 non X boosting to 3.64Ghz, on a 65W tdp chip... that to me screams awesome potential with overclocking. I think he might mean, the X chips have XFR so might overclock better at stock?
XFR range was barely mentioned by him, he said 100Mhz more but it's unclear if that is the best you can expect on any cooling, or on stock cooling alone?
1700 for the price and potential binning for lower power usage to me is the chip I'd want. The others just seem too expensive to me, and anything less than 8 cores just isn't an upgrade from the 5820k, not really anyway.