Electron is more active than NW.js looking at their github repos, it has had 25 releases since the last NW.js release for example. Visual Studio Code choosing electron was a big external validation too in my opinion. (no idea if that was a factor though)
Interesting. I am developing a desktop app using nwjs because a) many popular apps were made using nwjs and b) I like their documentation.
It is fascinating because both of them are quite similar in nature and picking one instead of the other doesn't mean you're missing out on a major feature.