Tower, Nearly all of the knives in the kitchen are carbon Sabatiers of one sort or another.
Yes, they do have an interesting history. I suspect it's even a little more interesting than the official version, in that the timing makes it likely Thiers-Issard (or one of the Sabatiers folded into the brand) hid them from the French and then the German government during the wartime steel drives.
As to how they compare from a performance standpoint... In order to get the best performance out of them, they require some thinning especially around the heel; and that can be a little bit of a challenge because of the full fingerguard. On the other hand, it's not an insurmountable challenge.
They sharpen faster and easier than a typical Japanese carbon, but won't get quite as sharp -- especially when compared to the best carbons.
The handles look primitive, but they're incredibly comfortable. Plus, they're full size no matter the size of the knife. With a petty (aka 6" slicer) that's a wonderful thing. With a paring knife, it's ridiculously, revolutionarily, delovely, delightfully, dewonderful.
F&F is as variable as Japanese knives in the same price range -- which is to say quite variable. It's important to communicate with The Best Things before buying and let them know what your expectations are -- watch out for bent tangs.
OOTB sharpening runs crummy. It's an edge you'll want to take care of with a thinning and sharpening as soon as you get the knife. That's not unusual for Japanese knives, either.
Chef's knife profile: As good as it gets. Just a great knife, as good as the K-Sabatier au carbone. What can you say? France wins.
Edge holding: Good compared to other European knives, but lousy compared to almost any Japanese. The blade alloy balance is tilted towards toughness as compared to strength. That is the knife will wave and even occasionally roll, more easily than it will micro-chip or chip. That doesn't mean it's impossible to chip though.
Edge maintenance: Can be maintained very easily on a steel. As said already, they sharpen very easily too -- which includes "touching up" if you've got the discipline to do that. Me, I usually don't go back to the stones until the steels don't work anymore.
That's something you want to do before you buy, particularly if you're buying a knife that needs work ootb.
Carbon is a great choice for some people. The real issue isn't how much extra care it needs (not that much, really), but that it needs it right away. "After dinner" isn't a good option with carbon. Maintenance aside, it's more sharp more easy for less money.
Y'know, I don't. Make a list of those knives at JCK which interest you and shoot an email to Koki. He's very good on the whole customer service thing. Under some circumstances, which probably have something to do with the amount of the order, JCK would convert bevels to neutral or lefty either at a farily nominal price or for free. I don't know whether that was or is Koki's policy, and wouldn't bring that up unless and until I was serious about pulling the trigger.
Remember though, no matter how it comes from the factory you can, should and will profile the knife so it suits it, you, your use, and the way you sharpen.
Hope this helps,
BDL