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)