Z170 requires a bios update for kaby lake chips, so you would need a skylake chip on hand to update the bios to support kaby lake.
Z270 would be the better choice to assure compatibility. I just recently upgraded to a 7700k and asus strix Z270F mobo. It has worked great so far I really like the bios and fan control software, very easy and intuitive to use. I have my memory running at 3000mhz cl15 without issue, and have overcloked the 7700k to 5ghz without issue. Seems like a great board so far. I personally couldn't justify the money for a maximus or hero board, I dont see what you are paying for. I also considered the gigabyte Z270 k7 in the 200 dollar price range, that looks like a good board as well with admittedly more features...