Here's what I have to say about today's state of version control systems in Free Software:
We shouldn't forget that a VC system is just a development tool. Preferring one over the other is nothing that has any direct influence on code quality, it doesn't make your algorithms perform any better, or your applications look prettier. It's just a tool. As such it should just do its job and get out of the way. A programmer should have religious arguments about code quality, about algorithms or about UIs, but what he certainly should not have is religious arguments over the feature set of specific VCSes.
Does this mean it doesn't matter at all which VCS to choose? No, of course it does matter a lot. The step from traditional VCSes to DVCS is a major one, an important one. Starting a fresh new Free Software project today and choosing CVS or SVN is anachronistic at best.
Which leaves of course the question, which DVCS to pick. If you take the "get out of the way" requirement seriously than there can only be one answer to the question: GIT. Why? It certainly (still) has a steep learning curve, and a steeper one than most other VC systems. But what is even harder to learn than GIT is learning all of GIT, Mercurial, Monotone, Bizarre^H^H^H^H^H^H^HBazaar, Darcs, Arch, SVK at the same time. If every project picked a different VCS system, and you'd want to contribute to more than just a single project, then you'd have to learn them all. And learning them all means learning them all not very well. And needing to learn them all means scaring people away who don't want to learn yet another VCS just to check out your code. Fragmentation in use of VCSes for Free Software projects hinders development.
Which brings me to the main point I want to raise with this blog story:
It is much more important to make contributing to Free Software projects easy by choosing a VCS everyone knows well -- than it is to make it easy by choosing a VCS that everyone could learn easily.
So, and which VCS is it that has a chance of qualifying as "everyone knows well" and is a DVCS? I would say there is only one answer to the question: GIT. Sure, there are some high-profile projects using HG (Mozilla, Java, Solaris), but my impression is that the vast majority of projects that are central to free desktops do use GIT.
Certainly, some DVCSes might be nicer than others, there might be areas where GIT is lacking in comparison to others, but those differences are tiny. What matters more is not scaring contributors away by making it hard for them to contribute by requiring them to learn yet another VCS.
Yes, with CVS, SVN and GIT I think I have learned enough VC systems for now. My hunger for learning further ones is exactly zero. Let me just code, and don't make it hard for me by asking me to learn your favourite one, please.
Or in other, frank words, if you start a new Open Source project today, and you don't choose GIT as VCS then you basically ask potential contributors to go away.
ALSA recently switched from Mercurial to GIT. That was a good move.
So, please stop discussing which DVCS is the best one. It doesn't matter. Picking one that everyone knows is far more important.
That's all I have to say.
 Of course, unless he himself develops a VC system.