[tzs]

Here's a video [1] by a math grad student showing how he uses a Surface Pro with OneNote for his math note taking, annotating papers, and stuff like that.

It can search in handwritten notes, and can convert them to text (including converting handwritten math).

I don't do enough math writing or note taking to justify the cost of a Surface Pro, so don't personally know if it really works as well as it appears to in the video.

[1] https://www.youtube.com/watch?v=C7OROShRVzQ