I'm kind of, well ... pretty much all, 'old school', and lean toward a simple sharpening stone/s and developing some manual skills. But if you want a quick and easy solution, perhaps you have a lot of knives and use them a lot, and are willing to pay the price for quality (over $160), the Chefsdhoice -120 got good reviews on Americas Test Kitchen. Uses diamond wheels and is supposed to last a long time.

http://www.kaboodle.com/reviews/chefschoice-120-stainless-steel-electric-knife-sharpener

Being a dedicated preper your going to want to keep a stone around and practice enough to know how to use it because the depends on line power. So the real saving is in time and labor.