It's really really comfortable. Maybe an 8 or 9 (I suppose I'd reserve a 10 for "the womb").

I've always had a hard time figuring out what to do with my arms though, as I either hang them down by my side, or sort of fold them on my lap, so for years, the chair has mostly been "occasional seating".

With the arm mount though, I end up having a really comfortable typing position.