I had been a long time Subversion user even before I started my company. Since 2006, the data analytics core of Lokad had been managed over SVN which proved to be a very robust piece of software (combined with TortoiseSVN).
We had a few hiccups where the easiest way forward was to delete the local version and check-out again, but otherwise, our SVN hoster has been operating flawlessly over 5 years, which is a long time as far software technology goes.
After more than 13,000 commits over SVN, we have finally migrated the forecasting core, the 2nd most complex software part, right after accounting and billing :-) toward Git.
Internally, after hesitating a lot between Mercurial and Git, we finally opted for Git primarily because of GitHub where we now host our open source projects.
There is a bit of nostalgia looking at good old tools depart. I am wondering whether Git will last for the next half-decade, or it will be supplanted by something that will make it look pale in comparison.
My personal take for the next 5 years: Git will stay but the technology battle will displace itself toward the collaborative tools that operate over Git (or Hg).