AWS: Predictable, and lots of managed services. I use it at my full-time job, so I didn't have to spend too much time figuring things out. The main services I use are EKS, ELB, S3, RDS, IAM and private VPCs.
Cloudflare: I use it for DDoS protection, DNS, and caching static assets. It currently shaves off 80% of the egress charges from AWS. Not sure