It needs a lot of massaging, at least for my handwriting. But it's been a while that I tried it with an actual pen. The main problem is that it recognizes strokes, so if you go back and close a gap in a symbol to make it appear right the recognizer will think you changed o to σ or something like that.

Back in uni I was able to take math notes quite well by typing in Word. The math notation there is similar enough to LaTeX (including most macros for symbols) but types much faster. But that's not handwriting, admittedly.