Time to clone is not directly a function of absolutely repository size.

Both Git and Mercurial use hardlinks for local clones by default, so the reason why Mercurial is slower than Git for local clones is primarily that its repository data generally contains more files.

Cloning/pulling/pushing speed across a network is in large part determined by the protocol used; a few years ago, Git's network performance was inferior to that of Mercurial [1]. I believe that has been largely fixed since then.

Finally, Mercurial allows you to have local feature branches that you can delete if they are abandoned just fine.

[1] https://code.google.com/p/support/wiki/DVCSAnalysis -- footnote 1

Your citation is comparing the "dumb http" protocol, which was replaced several years ago with the smart http protocol in git-1.7. Dumb http was only ever provided as a method of last resort. The git:// and ssh protocols have always been fast.

Another data point: when we converted to Git, I did a number of speed comparisons. Our repository was 77MB in Git versus 178 MB in Mercurial. Clone time from bitbucket over either (smart) http or ssh was 18 seconds with Git, versus 2 minutes with Hg. We can do a shallow clone (--depth 1) in 4 seconds (10 MB transferred) with Git, but Hg has no comparable feature.

The speed was also slower for the native protocol if you read the footnote to the end. Also, as I noted, this was years ago. I was making a point about cloning/pulling/pushing speed being dependent not on just the repository size, not about the relative superiority of one or the other tool [1].

[1] I find both Mercurial and Git adequate, but lacking in some aspects that are important to me (both with respect to architectural design and workflow considerations). For practical work, I consider the differences between Mercurial and Git to be relatively minor in comparison and cannot really get exercised over them.

Is it really helpful to provide numbers that you know are many years out of date? If you're really interested in this, try to import a big repository like, say, the Linux kernel using the latest version of Mercurial and see how it compares to the latest version of git.

I was making a point about what factors influence clone performance in general, not trying to contribute to the tedious Git vs. Mercurial debate. If I had found any data about, say, Gnu Arch vs. Codeville (or some other abandoned codebase), I would have used that instead.

Mercurial has "hg clone --uncompressed", which really cuts down clone time at the expense of bandwidth.