S3 offers some multi-region replication facilities, but as far as I’ve seen they all come at the cost of inconsistent reads - which greatly complicates application code. GCS dual-region buckets offer strongly consistent metadata reads across multiple regions, transparently fetch data from the source region where necessary, and offer clear SLAs for replication. I don’t think the S3 offerings are comparable. But maybe I’m wrong - I’d love more competition here!
https://cloud.google.com/blog/products/storage-data-transfer...