Beware: S3 doesn't support "+" in filenames (properly)
Discovered this issue the other day.
While you can upload a file with a plus "+" in it, it won't reject you. However, you cannot directly access it. You can only access it by encoding the "+" to "%2b" - so unless you are doing that in your links, you'll wind up with "access denied" S3 XML error. Because the "+" is interpreted as a space - instead of the actual "+"
While they could fix this, it looks like they won't at this point, as it will change the behavior that everyone is used to. I found some threads from years ago complaining about it, even back then there was little expectation the behavior would be changed.
Total complaints with S3: 3
Total happiness points with S3: 1,292