This query only considers CDNs where the base page is accelerated via the CDN and not necessarily only static assets being offloaded to a CDN in the classic sense
select COUNT(1) num_samples,
cdn CDN,
NTH(90, quantiles(speedindex)) p90_speedIndex,
NTH(90, quantiles(TTFB)) p90_ttfb,
NTH(90, quantiles(renderstart)) p90_startRender,
NTH(90, quantiles(onload)) p90_onload,
NTH(90, quantiles(fullyloaded)) p90_fullyLoaded,
NTH(90, quantiles(bytestotal)) p90_byteTotal
FROM httparchive:runs.latest_pages
where cdn in ('Fastly', 'Cloudflare', 'Amazon CloudFront', 'Edgecast', 'CDNetworks')
group by cdn
order by p90_speedIndex;
results in the following
Please note that this does not necessarily mean any comparison across CDNs (which cannot be done given the dataset) but rather answer whats the expected (in the statistical sense of expected) distribution of onload/speedindex,etc for a customer of an existing CDN (that also accelerated dynamic traffic).
As you can see barring Fastly the rest of them are fairly close within a range (Fastly may be an outlier due to the number of samples)