I've been using a Mead pen-based tablet with paper-like display for that. It has some disadvantages but it's been rock solid, no firmware patches or security exploits so far, and maintains state ridiculously long without needing battery recharges.
I was emphasizing that E-Ink devices with EMR pens provide an input experience very close to writing on paper. Combine that with all the advantages of actually having a digital document. The EMR pen never needs charging, and the E-Ink device gets charged on the weekend.
