The Graffiti 2 (I think it was called) on my Palm E2 was excellent.
Graffiti has been used on tablets a few times and IMHO it is better than some of the Microsoft efforts, but it requires the user to adapt to a strict set of special strokes when writing. Fine, but let me put it to you this way.
Newton 2 devices could read doctors’ handwriting and my signature correctly. Written in cursive, exactly as if on paper.
No general purpose recognizer intended for use by the general public has been able to do that before or since.