A couple of technical notes: > such as a repository structure optimized for performance Actually, repository structure hasn't fundamentally changed (unless yo

A couple of technical notes: > such as a repository structure optimized for performance Actually, repository structure hasn't fundamentally changed (unless you count the RevlogNG change in 0.9). There have been changes so that data on disk compresses better (the generaldelta change) and there's more underway to support new features (such as narrow clones), but they generally aren't performance-related. I note that this is a good thing: Mercurial's repository structure allows it to do things that aren't easy for Git, especially efficient random access to history (Git's structures are generally optimized for access close to HEAD and the root of the directory tree), at the expense of requiring more disk space. The performance improvements you've seen most likely come from more/better caching or reimplementation of time-critical code. > fast branches without making a separate working directory for each That was always possible. Documentation (such as the Mercurial book) suggested a clone-based workflow for reasons of convenience and because that's what people were used to at the time, not because you had to do it this way.