I used both at the same time at work for about 2 years, and mercurial was worse. Hg was slow, and the (custom) python plugins around it we used were frustratin

I used both at the same time at work for about 2 years, and mercurial was worse. Hg was slow, and the (custom) python plugins around it we used were frustrating (specifically, we had a build pipeline that used the mercurial module in python, along with an arcane scons thing) and there were some specifically irritating pain points like bookmarks and shelve that didn't seem to work properly. I mean, I get it, network effect... but all I can say is at least some people (like me) tried both and pick git on technical merit.