Hiding complexity from the user is mostly good; it's a shame that the replication service isn't more capable.
What negative experiences have you had with Dropbox + VCS?
I have 2+ side projects or submodules under development at any given time. I've been storing them in Dropbox for the last 3 years. I've been working on them actively from 3 different machines (two Ubuntu desktops and one OS X laptop), and they're turned off -- so not syncing -- when I'm not using them.
All that said, I haven't had one single problem. So empirically speaking, I don't see any problem with the mechanics of .git folders in Dropbox.
(Note that my key files, API keys, etc. are not synced to Dropbox.)
To be honest, I haven't tried storing git repos on Dropbox so these are just my assumptions based on dropbox usage for other files. I am just afraid that it may end up corrupting my git repo.
First of all, Dropbox will not overwrite data. If it finds a conflict, it will save a second file with "[machine name]'s Conflicted Copy" and the modification date at the end.
This hasn't happened to me with any git files yet, however, because my machines are always online. That means my working tree is always the same across devices and my .git folder is always identical.
The only way a conflict would be created is if I committed while working offline and then committed on another machine while working offline.
If that happens, I could just grep my Dropbox folder for files with "conflicted" in the name and remove them. Or, because I committed my files to a remote (often Github, but sometimes others), I could just delete the local copy and clone.