I have two Mad Dog Mirage X, an Operator and a Hunter. If you ask how these compare to steel, the answer is easy: nothing in common. You probably have to elaborate more on your question, because ceramic and steel are two different entities. But here we go.
Ceramic edge is really hard, meaning it will cut and cut almost anything, including steel and glass (well, if you want to spend the whole day doing it anyway). The edge won't roll, but will chip if you apply some suddent impact (no dropping onto hard surfaces). And no prying either! Edge deterioration due to abrasion is minimal. And there's no fear of corrosion to speak of.
Ceramic knives can be resharpened with diamond and Silicon Carbide, though I have no experience in sharpening it with the latter. Ask Cliff Stamp about this, he's more knowledgable than me.
The ceramic used in MD Mirage X is probably the most advanced now, compared to Pumas and Bokers. The first time I sharpened my Bokers, I ended up with chips along the edge. I had to be really careful in applying the force to get it done. So far no problem with my MDs, though it's still a long process compared to sharpening steel blades. But then again, the edge will be there longer.
Overall, I still believe in steel knives for everyday tasks.