From https://aws.amazon.com/s3/ and https://aws.amazon.com/s3/details/

    Data is automatically distributed across a minimum 
    of three physical facilities that are geographically
    separated by at least 10 kilometers within an AWS Region
    
    Designed for 99.999999999% durability and 99.99%
    availability of objects over a given year.
    
    Designed to sustain the concurrent loss of data in two facilities.

From https://www.backblaze.com/b2/cloud-storage.html

    Uptime: 99.9% SLA

    Reliability: 99.999999% durability

So S3 is 10x more available, 1000x more durable, and datacenter redundant.