I spent a decent part of last year testing various CDNs and this is not what I found. Cloudflare, Verizon were both better (performance, cache retention) than Akamai based on my testing. And cheaper, not even considering the cost of features that you'd have to buy from Akamai to make it a feature-equal comparison.

Performance testing for CDN is difficult, I'm not sure how accurate your tests were. It depends on many many parameters.