I recently went back to pen and notebook vs. taking notes on my iPad or Nexus. Turns out that taking notes by hand leads to significantly higher memory retention than taking notes by typing. If you want to remember, or recall, the content of a note, write it, don’t type it.
I haven’t seen any research that compares writing on a screen vs writing on paper and the resulting recall, but if it exists, I’d be interested in reading it.
If I need screen backup, my Nexus 7 fits perfectly against the back of a standard Moleskine notebook.