Every article I've read on this topic tends to say the same thing: Atom is a decent (but somewhat performance-hindered) text editor that borrows some, but not quite all, of the features and nice bits of Sublime.
Given this, why would I want to switch until it has parity with everything I've come to expect from being a paying user of Sublime?
For the UI. Atom is a significant update in user interface, and while there are performance dips (mainly at startup or using complex packages), the overall experience of using Atom has improved my workflow.
Interesting. I'll check it out, but unless I can get the same level of integration, super-fast file loads and searching, and parity with packages... I'm likely to not be a convert.