Using Google DNS, self-hosted resolver, or your ISP's DNS: NSA, your ISP, everyone and every dog at the middle of your link to the Internet can track and see your requests.
Using CloudFlare's DNS w/ DNS-over-HTTPS: only NSA (via a NSL or subpoena), Cloudflare and CloudFlare's upstream can track and see your requests. And I guess 10%-20% of the domain names already use CloudFlare, so for some domain, it's end-to-end encrypted, nobody but NSA and CloudFlare can track you. Even better, Cloudflare is experimenting with peering to upstreams (e.g. Facebook) using private encrypted connections, so the point-to-point encryption ratio would be even higher in the future.
Therefore, using CloudFlare is a net positive.
But one also needs to consider its second-order effect: is giving CloudFlare more leverage over the Internet infrastructure in the long run an acceptable choice over unencrypted DNS? I guess everyone has a different opinion.