I've owned a variety of ceramic knives and have been very happy with them. I started off with a pair of kyoceras that I picked up a going out of business sale for ~$20 each. I treated them extremely delicately and only lost them due to other people snapping them. After that, I picked up a few chinese no-names via ebay where you can get an entire 5 piece set for $30 shipped from HK. I treat them like crap - and consequently the tips of most of them have broken off, but otherwise they have been great. I use them to in place of a utility knife to cut cardboard and twine and they are still good to go in the kitchen too.
The downside to ceramic is that it's brittle - so you can't ever apply torque to it and the tips break off easily (I've seen some with rounded tips to avoid that problem) - the upside is they are ridiculously sharp and hold their edge for so long that sharpening is practically never required.
At kyocera's full price, its not worth it. But the no-name chinese ceramics are well worth the money.