-absolutely free
-works on smart phones and tablets
-recognizes almost all handwriting styles, no matter how messy
-no special way of writing is necessary, simply write naturally as you would on paper
-scratch out gesture makes it easy to delete symbols and numbers
-supports all basic operations, powers/exponents, brackets, trig and inverse trigonometry, logarithms, and constants
-easier and faster than typing into a calculator

Overall Pros