There are a number of features Fastly has which others (excluding eg Akmai) don't which make head-to-head comparisons more difficult. I have no doubt that Cloudflare is very fast in perfect conditions, but there were a much higher number of cache misses because there's less flexible configuration which did literally make the difference between 20ms vs 200ms in production.
As I understand it a charity may get the former thing for free through https://www.cloudflare.com/galileo/ , but the latter probably still has usage-based billing.
Comparing CDNs is incorrect by an aggregator. I couldn't find CDNPref methodology. One patient goes to two specialist doctors and returns with two different assessments (observer error). The multitude of variations in Cloudflare and Fastly alone, make it hard to compare. Free plans should be removed, and maybe just compare Enterprise to Enterprise on the same price point.
Cedexis is also a good tool to measure, while most of it is a paid product, they have a few reports you can see. they also list cloud providers, and have other reports such as throughput, etc.
Is there any documentation on how they measure it? If they're running tests from data centers / peering points or testing things which are highly-likely to be cached the results are going to be harder to generalize to normal usage.
