An electric knife sharpener looks like it would remove entirely too much material. I'm sure it would make a keen edge, but you would not want to do it very often.
I use various stones from 1000 grit to a norton 4k/8k, then a strop with chromium oxide. I have these primarily for honing my straight razors, but periodically do my kitchen knives as well. Yes this method is slow and really expensive.
I also have a chef's choice that keeps kitchen knives shaving, which I use the vast majority of the time. It's sharp but not as keen as on a stone.
With the stones and strop, I'm able to cut a hanging hair with a kitchen knife, which is a hell of a thing.