Git-style branches are called bookmarks[1] in Mercurial and "rebase -i" is called histedit[2]. It works pretty much the same.
Is there a reflog, though? When I mess up a git rebase, I have confidence I can always undo the rebase and try again.
When I used Mercurial, admittedly over five years ago, there wasn't a reflog. Sure, you'd get some .bak files when editing the history, but that's nowhere near as safe.
Have a branch-a that depends on branch-b that depends on branch-c that upstream just rebased and squashed some of its commits? More often than not `hg pull && hg evolve` is all you need to do to synchronise everything. This makes stacked PRs much easier to manage.