I host bunch static sites and have done benchmarks around TFTB and general network performance. Netlify is fast and most people won't notice much difference since the web page will be cached after the first visit.

Cloudflare is faster, you also get http3 over http2. Also Cloudflare has much better peering around the globe. When I do traceroute it's fewer hops compared to Netlify. I have tried vercel but haven't tested it extensively they use AWS and Cloudfront. If you use Github pages or Firebase hosting they both use Fastly. Fastly is also really good, in certain regions Fastly has better peering with ISP over Cloudflare. At Least where I am located Fastly is faster, but both Github pages and Firebase hosting doesn't have support for http3. On a fast network between h2 and h3 you won't find much difference. On a unstable or slow network h3 makes a big difference.