Zen 2 is releasing Q2 this year at 7nm. The 3700x is speculated to be 12cores/24 threads 4.8+ ghz, $330 MSRP. If true, Ryzen has Intel beat by miles for the next few years. Intel hasn't even shrunk to 10nm yet and likely won't until 2021-2022.
It depends on the use case. CentOS is a server distribution. Ubuntu is a noobie friendly linux distro. Use the one that best suits the user and application.