Have you considered Backblaze B2?
Performance is as good as Amazon, and pricing is considerably less. They also just announced full S3 API support so it can be a plugin replacement for Amazon S3 now.
If you do stick with a NAS solution, have you given any thought to ZFS and ZFS Replication?
At the moment we're using freenas OS, which uses ZFS. We haven't looked at backblaze b2, but might be an interesting alternative. I'm also interested in potential "decentralized" alternatives that just let the hive community do the hosting in some distributed fashion, with some guarantees on data redundancy.
I like the idea of decentralized community hosting, Siacoin style.
Perhaps an application similar to the Sia app could be built, but for Hive instead. You would log into your Hive account on the app and allocate some amount of disk space to be used for distributed file storage.
The blockchain would divide up a daily reward amongst everyone contributing their free disk space.
I imagine this would be quite an undertaking to design and develop, though. But I bet it would make Hive stand out even more.
If instructions or setup details are shared, I think it could be great for every app to have their own setup.
Backblaze seem interesting, I am trying it out on our instance.