Cloudflare's pricing is sneaky. They are good for small and personal projects with their free tier, but as soon as you need anything non trivial you get hit with their $xxxx/mo minimum commitment, "contact us for pricing" Enterprise plan. On Fastly you pay $50/mo (peanuts for a business) and that's it for basically anything you might want from a CDN, VCL is endlessly flexible and free. That $50 buys you access to a featureset that is arguably beyond Cloudflare's Enterprise plan. You will need quite a lot of traffic to go over $50, so overall it works out significantly cheaper for an SME that wants to use anything but a very basic CDN.
It's also important to remember that a lot of cases are perfectly served by VCL, I believe most businesses won't even need C@E. Sure, most people would need to learn a bit about it, but it's amazing to have it on your disposal for free compared to a usual rigid configuration.
Besides, something they don't advertise but is now the main selling point for me is support. Fastly was the only company I had pleasure dealing with where after shooting a technical question to their free tier support I got not just a technical answer, but a piece of code that solved the problem I had. In an hour. With a link to their Fastly Fiddle demonstrating how it works. When I encountered what looked like a bug, a few hours later their support person filed a PR to their TF provider fixing the docs. It was and is a breath of fresh air compared to my experience with any other SaaS, Cloudflare included.
I think the only thing that could've swayed me is Cloudflare's Chinese network. It's gated behind their Enterprise plan and they won't hold your hands much, but if you need it it's there.