People always claim this in mercurial posts, but it's really hard to tell to what extent this is just that people who are using hg all the time are familiar with the hg commands and so don't notice the problems any more.

As a irregular hg user, I frequently run into (or help others with) issues with the ui, like "why does `hg log require `-f` to do something useful", "how do I refer to the current head commit (protip: it's not `tip`)", "how do I see changes relative to a branch (bookmark) on a remote" and "which set of commands am I supposed to use for history rewriting nowadays and how do they work?".

hg has some nice features, but the idea that it's got a fully intuitive and uniformly well designed interface is, in my experience, a total myth. Which isn't to say that git has a great CLI of course, just that the extent to which hg is better in this area is often overstated.