Branching and merging in real life
At work I still mostly use Subversion for version control. Its main selling points: stable, performs as expected, integrates nicely with Trac, holds all our old stuff (legacy inertia).
Note that “pain-free branching and merging” is not on that list. (And don’t give me the old “branching is cheap in svn!” line. It’s not about the branching, it’s about the merging.) A couple years ago I started also using Mercurial and plan to eventually replace svn with it entirely. The aspect of Mercurial that made my life better recently is its support for branching and merging.