I would go as far as to say it's VERY usable. I and many of my colleagues use it every single day. I can't recall it ever crashing on me.

It's been more stable and usable than TextMate 1 for me for about a year I think (maybe more, my memory isn't so accurate); it's been my editor of choice since then, replacing TextMate 1 which was my editor of choice since it first came out.

It's my editor of choice at work. I use it daily. Have never experienced crash.