They look similar. I'd like to be proven wrong and GitHub make Sublime a more maintained and transparent project, but it's doubtful.

I think if this kicks out good and will have plenty of plugins sublime will be dead in a matter of months.

The UI is undoubtedly similar, but Atom appears to be written in Coffeescript. Isn't Sublime written in C and Python?

Couldn't this effectively be "Sublime Text 4," written from scratch using ST3's proven approaches? I honestly have no clue, I just want to believe.