$0.25 /GB is pretty expensive. I'm using Hetzner Storage Box [1] which has tonnes of connectivity options where 1TB is only 9.40€ (works out at 0.0094€ /GB)
Have they been around for long, and you know of any external public audit that has been done on them?
They are DIN ISO/IEC 27001 certified: https://www.hetzner.com/unternehmen/zertifizierung. Of course if you only store encrypted data you don't really need this auditing.