Theoretically it is, but on one Linux computer I have it freezes from time to time, whereupon it stops redrawing frames, resizing the window results in gray rectangles etc. I think it’s caused by a slower disk, which is sad, because I don’t think that’s a legitimate reason for a UI to stop working. I can accept having to wait when opening a file, but the UI completely freezing is unacceptable. I typically close and open it again in those situations.

It still has a faster fuzzy file search than anything available in Emacs, which is why I stick with it.

I think it is, or at least I use it all day every day and its memory usage is good for me.

I second this. Sublime text is one of the faster text editors out there. It boots fast enough that I use it as my go-to notes app.