Personally, using the Windows 8.1 client has been pretty fast for me, maxing out my upload. Unfortunately, I have pretty slow upload so it takes me a month to upload a TB.roggers wrote: ↑Office365 is great but, extremely slow on OS X (has taken over a month to upload 400 GB especially since it does it "one file at a time" and needs to process/scan all directories every time it launches). There is no harm in having multiple services (i.e. Amazon Cloud for Photos which is dirt cheap).
Amazon's desktop app for photos is incredibly fast, capping my upload speeds at nearly 9GB per hour or 216GB for a full day.
I'm currently working on a Python client to upload/download files from the command line. I hope to have something done in a few days, though it may not be too robust.
Amazon support indicates that the file size limit applies to web uploads and the Mac/PC clients don't have this limitation. I haven't tested the API yet so I don't know if that has the same limitation.