In alphabetical order:
A nice knife, but not exactly "carbon," as everything on the outside but a fraction of an inch of edge is stainless.
If you're really enamored with the idea of an Aogami Super hagane in a san-mai knife, the Hiromoto is a reasonably priced way to do it.
I bought four of them about three years ago for our own use, and ended up giving them away or selling them very quickly.
They sharpen fairly easily, but don't steel very well. The handles are slender and not particularly comfortable for someone who doesn't pinch. The profile is OK, but not great. Fit and Finish is usually pretty good; but there's a lot of weirdness with the factory edge. As with nearly old Japanese knives, plan on sharpening it to how you want it ASAP.
Linda didn't like the handle or the profile compared to "her" Sabatier. The handle didn't bother me much, but I hated the "dead" sensation it turns out I get with all san-mai and warikomi. While it's not exactly unusualy, the large majority of people don't seem to feel and/or care about it. If you've ever tried a Shun, you either know or don't know what I mean.
Lots of people swear by and love them. I can't recommend.
Great knife. The Misono Sweden has a better handle (for most people) and an engraved dragon. The Kikuichi is a lot less reactive. They're very much in the same class. I only mention it because you might not have heard of them.
Same group as the Kikuichi and Misono. Slightly more agile profile than either of those. Masamoto "feel." Not as attractive as the Misono, and not as good as the HC. Same handle issue (if there's an issue at all) as with the HC.
Trade my K-Sab for a CT? No.
As far as I know, the best, mass-produced, western handled chef's knife made.
Masamotos are special. Why? Nothing particularly stands out. They're not the hardest, the thinnest, the best shaped handle, the most expensive alloy... But the way everything works together? Oh baby oh baby.
I'd rate the Masamoto CT as overall in the same group as the Sabatiers, but the different alloy in the HC puts it a cut above.
There's one known F&F issue that cropped up a couple of years ago with western handled Masamotos in general, and that's bad handle scales. My impression is that Masamoto has pretty much taken care of it. But, if you decide on an HC, you want to communicate with the dealer to make sure that yours were fit and installed correctly.
That's the only negative. I can give you more of a rundown on the positives if you like.
The one thing which stops me from saying, "just buy it," is that price seems to be driving you towards a 21cm HC instead of 24cm. As good as HCs are, if 24cm is the right length for her she'd be better off with a 24cm Misono or one of the 10" Sabs than a 21cm HC.
An excellent knife. It competes in price with the Masamoto CT and Kikuichi Elite, also very good knives. There's not much I don't like about the Misono. Excellent profile, excellent handle, and the engraving is nice. The alloy, whatever it is, is highly reactive; you'll probably want to force a patina rather than going with a baking soda regimen.
Excellent edge characteristics. May be profitably maintained on a steel, but use a good seel and be careful. Great handle. Very good profile. Good F&F. Great alloy which can be sharpened to stupidly acute edge angles and serious asymmetry -- if you like that sort of stuff.
Sharpens quickly and easily. Can be steeled profitably. You'll want to "touch up" pretty often though, to keep corrosion off the edge.
Mario Batali, who does not seem to have an endorsement deal, uses one -- for whatever that's worth. His, by the way, has a forced, "mustard" patina.
Would I trade my Sabatiers' overall excellence for the Misono's better edge holding and better slightly better edge taking? Maybe, maybe not. Highly recommended.
K-Sabatier and Thiers Issard market several lines of excellent carbon knives, particularly K-Sab au carbone; K-Sab "Canadian;" TI carbon; TI "Massif;" and TI "Nogent." They're softer than Japanese knives and need regular steeling to maintain their sharpness. On the other hand, the edges don't need to go to the stones very often. And yes dammit, you do have to sharpen around the finger guards. You can sharpen on oilstones or waterstones without any issues, and to an edge angle even more acute than the nominal "Japanese standard" of 15*; and with some asymmetry at that. They'll take and hold a serious polish, too.
They feel fantastic in your hand, in the cut and on the board. Nothing quite like one, really. When it comes to the gestalt of a knife, it competes evenly with Kikuichi and Misono. It's only superior is the Masamoto HC.
I sort of collect Sabs and own at least one of every type mentioned. Highly recommended.
You've undoubtedly got sufficient reasons for not bringing up Sabatier on your own. An 8" knife is short, and a very poor substitute for a medium 9-1/2" or 10", so that lets HC out. CT and Kikuichi are just that little bit of a whisper behind the others.
Misono Sweden 24cm for the win.
Don't forget to tell us what you choose,