I've heard that the new ones (post-1985) aren't as good as the old ones. I don't have firsthand experience as I only have kind of old (1970s) and pretty old (1950s NOS blade) ones; there's some members here who have really old (>100 years) ones. Anyhow, my 12" NOS is a great knife, one of my favorites. I mostly use it at home, but it will stay sharp through a shift at work, which is as long as I require. Exquisite profile and geometry, and with the distal taper it can be used for many tasks that don't necessarily call for a huge knife. My 6" utility is also a great knife, gets wicked sharp and also has a nice profile for a petty. The 10" chef could benefit from thinning at this point, but I decided not to grind off the natural patina, pits and all. That one will eventually get retired, I think, rather than refurbished.
Short version: yes, nostalgia, and familiarity; I would say these are some of the better knives one can get without having to learn new cutting and maintenance techniques.
Long version:
I think there is certainly an element of nostalgia -- after all, these are probably what Escoffier and Careme used, as well as Julia Child and Jacques Pepin. The companies are still in business under the same names and trademarks (although it is important to know which is which before buying) and the knives are easily available in North America, whereas, for example, an older Sheffield knife is presumably just as good but I couldn't say which to buy without a fair bit of research, or if any current offerings are on par with the vintage stuff. The knives have a classic, understated elegance and the use and care thereof is familiar to Westerners; a carbon Sab might not hold an edge as long as an R2 gyuto, but it can be brought back to very sharp with the steel rod found in most home and commercial kitchens and sharpened on common oilstones. They feel very comfortable in the hand at any size: the 12" is not at all cumbersome or unwieldy such that I almost think I should have gotten the 14". I don't feel at all nervous using them to cut through chicken bones, hard rinds, partially frozen foods, all the things you shouldn't use a J-knife to do.
In my admittedly limited experience, Japanese knives (and by extension, knives made in the Japanese style in terms of profile, geometry, and steel characteristics) cut more cleanly, more precisely, and more easily. They get sharper and stay sharp longer. I had to learn different cutting motions and methods of sharpening and maintenance, and purchase some water stones, but to get the same results from my French knives I would perhaps have to have much more practice and training.
