But I still have problems with pen and paper.
I like the ability to add to notes and change them. Professors sometimes meander about in lectures, and I sometimes want to reorganize the ideas they present.
You cannot search efficiently with paper. I have terrible hand writing on paper. Papers wrinkle and drive me crazy. I write slower than I type - and it's assumed (by professors) that people are typing so they teach at that speed (ppt doesn't help). Paper cannot be as easily shared as documents.