It really is a matter of HOW you go about writing the notes, not just the medium you use. I type all my notes. I even type up my maths notes these days.
The main reason is organisation. You have control - you can edit, cut, copy, shrink, enlarge, add a picture, highlight a section, add some more crap here or take some crap out there. My second reason is that it is far more compact. Since you have that control, your notes are ridiculously smaller. A smaller set of notes mentally makes it feel more comforting, as it feels like you are going through less.
If you're slow with computers, fair enough - not your thing. But I think one issue with it is that people literally transfer some textbook notes or class notes STRAIGHT to the computer. If you move text from A to B without any midground, your brain won't process anything.
Often what I do with my notes is make 'dot point notes' for maybe 3 textbooks. Often the notes from textbook B overlap with notes from textbook A. Then I sit down all of the jumbly-crap and I don't learn it by typing it up, I learn it by digitally trying to express the ideas of 3 very similar dot points (as in, bullets, not syllabus dot points) into a singular one.
^^ That may sound slow, but its not.
Its really a matter of how you go about doing the typing, whether you are computer literate and whatnot.
Handwriting = You remember more, but, the benefits and flexibility of typing outweigh that, you can easily compensate for a 40% less remembered by that flexibility.
At least, my 2 cents ;P