We choose Backblaze B2 because it makes more sense for storing static assets.
We admire Backblaze's customer service & transparency, plus, we trust them to maintain fair business practices - including not raising prices in the future.
Lower storage costs means we can keep more data for longer, and lower bandwidth means cache misses don't cost a ton.
We offer our customer HIPAA compliant storage. After analyzing the market, we decided to go with Google Storage. The Nodejs API is ok, still not ES6 and can be very confusing to use. For each new customer, we created a different bucket so they can have individual data and not have to worry about data loss. After 1000+ customers we started seeing many problems with the creation of new buckets, with saving or retrieving a new file. Many false positive: the Promise returned ok, but in reality, it failed.
That's why we switched to S3 that just works.