What is new is that you can compare branches for each implementation, as he has each implementation as a branch within the same repo now. This will help visualize the differences between competing frameworks. I think it is a race, and some consolidation is due.
Alex’s implementation-per-branch organization is better than the way that Addy Osmani’s todomvc.com single branch design in my opinion. Sure it requires a higher level of SCM adeptness, and Git/Github in particular, but people who have skin in the game are much more likely to look at the diff, feel somewhat insulted at the implementation, and donate back a patch. Of course we don’t have patches any more, we have GitHub pull-requests.
Github have a page/tutorial on comparison view here.