I wouldn't want to rely solely on an e-reader for survival information. Even though the e-ink versions are very energy efficient they are still relatively fragile. I guess it falls under the "carry a GPS but have a map too" theory.

I heartily endorse placing survival information on them as an adjunct though. Cody Lundin's 98.6 Degrees was on sale at Amazon for $1.99 recently for the Kindle edition. Even though I had the print copy, I bought the Kindle version because I could download it to any linked Kindle device - my iPhone, Kindle Fire, iPad, even my PC. If the best knife is the on you have with you then I suppose the best survival info is too.

If you want something concise and easily portable, Doug's RSK guide is great. No batteries required.