I've been testing the official Google Drive app for macOS and compared with DropBox the sync process is too slow over the same internet connection, we did the following test, uploaded a file in dropbox and the same file to Google Drive, in that scenario both services performed well, once you started working in the uploaded file, the problem became clear, after every change GDrive uploaded the whole file again, but Dropbox only uploaded the changes to that file. The result, Google drive is less expensive but slow than Dropbox when uploading the changes, Dropbox is more expensive but much faster because only uploads the changes to that file.