Akamai is used across the whole company as a content delivery/caching layer of our infrastructure, accelerating delivery of many different types of content i.e. images and web pages. It front-loads our e-commerce capabilities and a few other systems.
Akamai offers sophisticated security and defense layers in addition to its content delivery network. Its focus on security is well known and beats offerings from AWS and Azure to punches. It redefined the cloud security market by extending its core offering.
Akamai is a well-established brand name with a great product. It meets and many time exceeds the needs for global content delivery and security management layer at the edge. Fine grain security tuning seems cumbersome as the definition of the app keeps changing. It also requires an investment of time for the setup which doesn't necessarily make sense for smaller scale scenarios. Some products offered by AWS, Azure or the Google Cloud can be more tightly integrated with cloud provider offerings thus easier to configure.