FWIW, I'm used to seeing >95% from working with CDNetworks (and I believe that's even in their literature somewhere), which has a kind of (to borrow a term from a different kind of service) "supernode"-like model for their cache layer, proactively distributes cached resources, and does revalidation as a separate path from fetches.
As for their DoS "features", yes: they have a bunch of features because it makes them look like they are doing something worth value, but I am going to again remind you that somehow you never see websites that are using normal CDNs suddenly give up and give you an Akamai-branded captcha, and yet somehow they do not crumble under the weight of denial of service attacks; it just isn't the case that using CloudFlare is the only way to be safe from DDoS, and there's something weird about how the experience of using a CloudFlare website somehow is noticable.
One of the challenges here is popularity: if you're a major site, yes, Akamai will have content cached at most of those 140k POPs but sites with different blends of cacheability and global traffic distribution might see a better cache hit ratio with fewer POPs so things stay hot in the cache longer.
These are complicated services so the results are going to bay widely depending on what you need (e.g. having an optimized site means that every optimizer service I've tried made performance worse), and how much you can adjust your application to work with the CDN and tech changes like HTTP/2. The other reason why blanket statements aren't worth the time needed to make them is that these are not free services and you can get easily find cases where service A is better than service B but not enough so to justify the price.
(Add for the DoS tools, note that that's pronounced “feature” by most people and at least personally I never see them except when testing through a commercial hosting company's network. Tor users whine a lot about them but that's just entitlement and unwillingness to think critically about what a site owner sees from their peers.)