I do this to collaborate with 2 other people to write songs. It works very very well, we can all work on the songs, just not at the same time.
We use BitTorrentSync though because it isn’t space limited, but then its also not a cloud backup system either - it simply shares folders on our hard drives. Not quite what you’re after, but the synchronisation overhead should in theory be the same, and I personally leave mine running at all times, even when I’m using Cubase. I haven’t noticed any degradation.
To speed up synchronisation we moved over to using 24bit FLAC files (changed the default template). These are lossless compressed audio files and they are usually 50% smaller than WAVs so that really helps. It also helps that we’re all 50mbps fast internet connections.
Another band I work with occasionally uses Google Drive which has a large free 20GB limit, and that’s on Logic Pro X on Macs. I sync manually on this one, i.e. stop the syncing while working on the song. Occasionally I forget to stop the sync and I haven’t noticed any degradation in performance, but then that’s Logic not Cubase, and I’m only working in MIDI for those projects, on a macbook pro.
Can’t comment on dropbox because when I have to share through dropbox it’s free space is so small and limiting that I tend to share only MP3s or small WAVs through it!
For anyone interested in collaboration or local backup as opposed to cloud backup I’d heartily recommend BTSync. We share about a 20GByte (and growing) folder with oodles of song sub-folders. We’re on Win7 and I’m using Cb8 while the other two are on CbArtist8. We chose BTSync for this because it isn’t a cloud share but directly shares folder/directories between PCs (Mac or MS). There’s therefore no storage limit (other than personal disk space of whoever’s sharing) and our music isn’t in the cloud for hackers to get or for Google to use (note their T&Cs!) . BTSync is available free for a lite version too.
But, as said, BTSync is not using a cloud service so there’s no copy in the cloud, so I actually have another server machine on my local network which syncs as well so that there’s a 24/7 version of our work available at all times, i.e. when my studio PC is switched off and they need to sync, and vice-versa.
And also as part of the collaboration, to make sure we don’t work on songs at the same time we have a simple manual locking system. When working on a song the person creates an empty text file in the song folder with their name in the title. Then when they’re done they delete the file. Email communication, synchronisation and a quick eyeball of the folder before double clicking the .cpr file stops us working on the same song.
Keep us posted about your findings re Dropbox and any others if you’re testing them out…