I used Mercurial at work for over 5 years and never once had a stack trace.
The fact you mention it in reaction to a Git detached HEAD suggests you think that is an error condition / bug in Git. Although I hate Git, I know it well enough to know that a detached HEAD is not a bug and it can even be useful sometimes. Or maybe you're referring to half-finished rebases - those exist in Git too. If you did think these are bugs in Git then I think that proves how confusing Git is!
Git won over Mercurial because (1) it was released before Mercurial (by a fairly short margin), (2) it was written by Linus and that's a level of celebrity to devs that is hard to beat, and (3) it's the basis of GitHub (partly because of 1 and 2). If the top open source hosting service were HgHub, or Git had been written by some other developer, things could well be different. (But now that we're in this situation, I agree it's better to use Git like everyone else even though it's an inferior tool.)
The fact you mention it in reaction to a Git detached HEAD suggests you think that is an error condition / bug in Git. Although I hate Git, I know it well enough to know that a detached HEAD is not a bug and it can even be useful sometimes. Or maybe you're referring to half-finished rebases - those exist in Git too. If you did think these are bugs in Git then I think that proves how confusing Git is!
Git won over Mercurial because (1) it was released before Mercurial (by a fairly short margin), (2) it was written by Linus and that's a level of celebrity to devs that is hard to beat, and (3) it's the basis of GitHub (partly because of 1 and 2). If the top open source hosting service were HgHub, or Git had been written by some other developer, things could well be different. (But now that we're in this situation, I agree it's better to use Git like everyone else even though it's an inferior tool.)