I don't think it's a bad product, but I wonder what problems it actually solves. Personally, I'm not interested in this at all. It doesn't look like adding an X-module would be subject to code review. It's not clear what the auth story is around who can make these changes. There's a command-line client, but it's listed as unsupported on their website. X-modules require an extra application to manage the repo relationships. If you want to pin an external dependency, it's not clear that you can do that with an X-module (the screencast doesn't show it, I don't think). With X-modules, you are tracking a branch, not a revision. If you are looking at submodules to manage repo size, this solution is not for you. With X-modules, you have all the code in your repo, vs. This 'solves' the submodule problem by just copying everything, as far as I can tell.
