@Krandor is right, ACD is not bad in general.
The unlimited option was a very very cheap storage solution, but it came with some flaws. The biggest one for me to use it as the primary file storage were the unspecified limits. Amazon neither released limits for API calls nor file downloads.
Before I moved to Google drive I got 24h bans every second day with “normal” usage. This is not acceptable for regular usage.
Google drive has specified all limits. This way I can figure out how to avoid them by caching or slowing down requests.
The biggest problem with ACD is the “shared” API key. With Google each user can create their own key, but with ACD everyone shares the same… and if Amazon decide they don’t like it then they can ban it.
To see how a useless POS ACD is for me check this out: I just want to remove all my files and get to basically an empty drive SINCE SEPTEMBER : Proxy for Amazon Cloud Drive
I managed finally to get to a “stable” condition where everything is in trash but there’s no way to empty the trash! And files will not get deleted even after months, despite the warnings. Every now and then when I want to get annoyed I try to select all in browser but after a long-LONG time SOMETIMES it works and I can delete whatever the maximum number it can do at a time (1000-3000, can’t remember). I still have 100-something thousand files at this rate probably I’ll be done in 6-12 months.