> This new tier is deeply innovative, and Amazon will likely enjoy a monopoly on low latency object storages for the next couple of years.<p>I don't think S3 Express will be lonely that long :)<p>It looks like it already isn't - Azure Premium Blob storage promises similarly low latencies, and is available as a regional service. They also talk about the main distinction being SSDs instead of HDDs (<a href="https://learn.microsoft.com/en-us/azure/storage/blobs/storage-blob-block-blob-premium" rel="nofollow noreferrer">https://learn.microsoft.com/en-us/azure/storage/blobs/storag...</a>)<p>Google Cloud Storage is layered on top of Colossus, which I gather is a zonal service that can be SSD or HDD. Basing that on Bigtable, which stores its log and SSTables in Colossus, and lets you pick between SSD/HDD with the former enabling single-digit millisecond latency IO.