While there may be the occasional glitch, I use FTM and DropBox on at least two computers. So it does "work".
What I have found is that you should "sync" with only one computer. In my case I use a laptop and a desktop and sync only with the laptop.
Some cautions -
Don't use BOTH (or more tnan 1 PC) at a time. Dropbox is not a database manager, just a simple lock files and sync mechanism.
I had no problems with photos or any other files.
2012AP28 15:15 Sydney