Ask HN: What's your favourite version control system, network effects aside?

I realise that the advantage of using the same one as everybody else can be a nearly unassailable advantage. But putting that aside: what would you use for a new project if you had an entirely free choice?

Alternative formulation: are there any "Perlis VCSs" which are worth trying for the sake of the alternative viewpoint they offer, even if you don't end up using them long term?