Mountain Duck looks promising. For whatever reason the current solutions for SSHFS on Windows/Mac are slightly out of date.
The "blob" storage support however was pretty damn needed especially considering that you had to usually install dedicated software for each service you use to get that ability before, and the few universal projects that existed have so far been mostly abandoned.
ExpandDrive recently greatly enhanced their product by providing background uploads.
Used to be that the whole Finder would hang while waiting for a response from the server. I haven't tried recently to say whether that's still true.
Cyberduck also does S3 and the cloudy stuff.
