Yeah it has this weird UI lag, it always feels like using a website rather than an app to me, one of the reasons I always go back to sublime text (3) after trying out releases now and then to make sure I'm not being foolish or missing out on something better. I like the idea that it's open source but I really don't like the idea of it being a heavy javascript app, on my slower laptop you really notice it's memory usage after a short while also.