Swift/APIFeatureComparison
S3/Swift REST API Comparison Matrix
General compatibility statement
S3 is a product from Amazon, and as such, it includes "features" that are outside the scope of swift itself. For example, swift doesn't have anything to do with billing, whereas S3 buckets can be tied to Amazon's billing system. Similarly, log delivery is a service outside of swift. It's entirely possible for a swift deployed to provide that functionality, but it is not part of swift itself. Likewise, a swift deployment can provide similar geographic availability as S3, but this is tied to the deployer's willingness to build the infrastructure and support systems to do so.
Amazon S3 REST API Compatability
Amazon S3 Bucket operations are referenced here
Amazon S3 Object operations are referenced here