git is not only blazing, incredibly, ludicrously fast, but it has the largest development community of all the open-source version control systems around today. In other words, it has already won. And you know, I don't really mind all that much!

The theoretical possibility of a SHA1-namespace clash remains in the background. However, the Linux tree has like, what, less than a million objects? And a single SHA1 hash is 160 bits long. Even accounting for the birthday phenomenon, I don't think there's realistically ever going to be SHA1 clashes in git.

(Though I think the subprogram that writes new objects to a repository checks hash matches, that they're indeed the same data as would've been checked in. So there's no breakage even if the once-in-a-lifetime collision came up.)