Until it has support for plugins (namely μBlock Origin and LastPass), Microsoft Edge browser will not become my primary browser. However I find myself using it a lot.
Firstly, it starts quickly and is a great way to use the web without being signed in to Google, Facebook, Twitter etc. Things I used to fire up a Chrome Incognito window for I now use Edge for. It's also a pleasure to use, sites render properly and it feels fast and light. On my Dell XPS 13 2015 the two-finger scroll is smooth and responsive, something I can't say about Chrome.
Secondly, in the excellent developer tools there is one button in the debugger that has made debugging a lot easier: