Ubuntu. The #837 bug is worst, but there are tons of others... github.com/SublimeTextIssues/Co ... pen+ubuntu
On Mac there are issues in el capitan and frequent crashes as well.
The latest Atom is more than fast enough. And of course, "best" is highly subjective. Sublime doesn't even have proper github integration, which all developers I know off consider a must. If only the sidebar API was good enough, people would've written a package (the attempts out there are very weak)
Well, it's also incredibly buggy. Have you seen the issue tracker lately? There are literally 1000's of unanswered forums posts. People are struggling with Sublime. Fanboys don't like to admit it, but there are tons of bugs and annoyances in Sublime. That's also the case in Atom, but the difference is that they 1) care and 2) have the manpower to fix things.
I still visit this forum from time to time in hope that JPS gets back on track and releases a beautiful upgrade called Sublime Text 4.0 Awesome Edition.