i switched from wustof to sabatier carbon after working with another guy who used japanese carbon steel knives. i tend to not take my knife to a stone often, and i found that the carbon knives come back really well with just steeling.
i was a little worried about the carbon aspect, but, really, it's not a big deal at all. often, i forget to wipe it down or oil it when i should and it hasn't turned black or anything. a few times, i've put it away wet and the next time i look, it's rusty, but the rust comes right off when i scrub it with a scrubbie.
for me, the care and discoloring of the blade is a non-issue. i mean, who cares if your knife isn't totally chrome-shiny? better that it's really really sharp.
the only issue is, as someone mentioned, that certain foods will react. i find that if i cut herbs or lettuces with it, they tend to brown near the cuts faster than they would if cut with a stainless knife.
other than that, though, carbon rules!