As you need to store files and also need to serve the files through CDN like Cloudfront
Pros:
Easy implementation: Storing files and serving it over CDN with combination of AWS S3 and Cloudfront makes it easy like kids stuff. SDK is available for almost most of programming languages. Just point your S3 bucket with cloud-front configuration. You are done!
Security: AWS offers configurable set of access control policies
Pricing: Can bootstrap it upfront with minimal cost
Reliability and backup: As AWS storage service offers with plenty of replication and backup options with different regions and availability zones.
Integration with other AWS services: Like archival of files using AWS Glacier service. New AWS lamda service allows write event driven logic, e.g. On each image upload event (S3 put event) create its thumbnails or compress image before store it
Cons:
Experience with AWS S3 & Cloudfront: Recently I have built service in Indian region context. We evaluated AWS Cloudfront, Cloudflae CDN. In my opinion Cloudfront is far better than Cloudflare. As edge location for CDN is available in India and latency for delivery of file is quit low.
Sorry i'm not aware of other options. But yes you can host the files on other public cloud providers and serve the content over Cloudfront or CDN service. Try to do comparative analysis of them as per your requirement and priorities.