So far, I have been reluctant to use a DVCS. We have got Subversion and it does an excellent job, at least for me. Ok, the idea of local commits while travelling in the train is compelling, but we might as well have inexpensive UMTS flat rates in the future. Maintaining a local branch over a long time is not what I usually do.
But that's not the overall point, if you are curious to try something new (which I still am, at least from time to time). The killer argument against DVCS has been, IMO, that there isn't the DVCS: We've got Git, Bazaar, Mercurial, to name just the most important ones, not to mention Arch, Monotone, or Darcs. I'd be ready to learn using either, but definitely two or even three. And, until now, I never had the impression that learning one of them would be sufficient. For example, SourceForge does support no less than three different DVCS (as well as grandpa CVS and SVN).
That has changed: The ASF has now a read-only Git repository. Ok, currently it seems to be a one man effort by Jukka Zitting (while writing this, it just came to my mind that I owed him a Kudo on Ohloh), but the interest is obvious, as projects are already requesting to be added. Gnome has recently decided to move to Git completely. If you look into Bug 257706 on the Eclipse bug tracker, then you can't fail to notice that it sounds like Eclipse will have it's first Git repositories soon. (Also note the Git BoF.)
Similar news from Bzr or Hg are missing. Ok, Max Kanat-Alexander is pressing Bugzilla to Bzr (he deserved yet another Kudo, btw), Widelands has moved at least its web site to Launchpad, but the list of projects using Git (including Linux Kernel, Perl, Rails, Fedora, or X.org) tends to become more and more impressive.
Nough said, I'll give it a try. My main reservation will be the quality of JGit and EGit (in fact, these will be the most likely candidates for reasons to withdraw), but I should keep in mind that I refused to use Subversion because of the Subclipse quality as late as 2004. Let's see what the future brings.