[jillesvangurp]

You'd need some arguments for the assertion that mercurial is better. I think Mozilla is switching because of years of failing to come up with good arguments. And it looks like they gave it a lot of thought. That and an increasing dependence on git internally to the point where people were spending non trivial amounts of time engineering around mercurial and coming up with all sorts of hacks to enable git usage. At least, that's what the article suggests actually happened.

You'll never get consensus on X being better than Y in the tech world. There are always going to be people that insist Y is better than X. And more power to them. But you have to be realistic. There is a lot of stuff that just never gets a lot of traction. Mercurial is one of those things. It's like betamax vs. vhs.

Initially it looked promising and then Github happened and the rest is history. The whole industry now runs on Git and Mercurial sort of flat lined in terms of growth after Github started hosting essentially the entirety of the OSS world (with few but notable exceptions of course). At this point it's a hard sell for new projects and some of the larger remaining users are switching away or are considering it.