Another POV here, I moved from Visual Studio after using it for over 15 years. For me, Atom is fucking fast. Lack of UML diagramming, database designer and TFS integration is a blessing in disguise.
I love Atom. I've been using it since the day it was announced. But I don't use it for the speed. It still chokes on huge files. When I need to open something big, I reach for Sublime, and it handles it with ease.
I'm was still on 2013 and my install is almost 2 years old. VS seems to get slower over time. And this is without powertools or resharper. Maybe it is just me but Atom sure feels quicker.