Dropbox and Google Drive syncing the same folder at the same time, is it posible?
Solution 1:
Based on what Al Everett said in his comment, I backed up my files again, I started messing around with Dropbox and Gdrive, and found this:
GoogleDrive doesn't allow symlink-ing; it keeps saying "folder not empty", even when the original is indeed empty.
Dropbox, in the other hand, has no troubles using a symlink to any folder, as long as it's named Dropbox
So, both can sync to the same folder, as long as the Gdrive folder is created first and then Dropbox is configured to sync to a symlink of the "Google Drive" folder.
I guess it is a matter of time until the folks at Dropbox close that loophole too.
Finally, I added my own personal touch, by creating a symlink named "Cloud", pointing to Gdrive, and hiding both Gdrive and Dropbox on Finder.