The only place I would disagree is the fatality being a "better" board then the extreme4, as they are nearly identical in specifications, or identical except for colors scheme.
the differences are "gimmicks" and stuff not of real importance. the important stuff is power phases (both have 12) ...PCIE (they both have 3 or 4 i forget), USB options, (they are the same or pretty close)....they both support optane (gimmick) ..... and they both have those dingus RGB's (gimmicks) .... the extreme has dual UEFI, im guessing the fatality does too (possibly needed) ... the main difference when i bought mine, was the extreme was cheaper than it is now, but ive been buying the extreme series since Sandy bridge, they never let me down. Asrock is always the best choice in MoBo tech, either are great boards, basically the same.
https://www.asrock.com/mb/compare.asp?Models=Z370 Extreme4,Fatal1ty Z370 Gaming K6
honestly, id argue that the taichi isnt "better" than the Extreme4.....they OC the same, and are both tough as hell. All the rest is bells & whistles, which is important to some, but im not the kind of guy to pay $100 more for a 4th PCIE slot, or more RGB lights, etc.
Best buy IMO/IME for the $$ is extreme4, as ive beaten many guys running taichi boards in OC, and bench tests. but $160 is a bit high imo.....maybe they'll go on sale.