Vintage blacks are an expensive gamble, especially in this day and age. Unless you're buying from a reputable harvester, which requires some effort on your end finding people who know their stuff and not looking for a quick buck, they're almost never worth it. The name alone brings up the price a lot, and the pool of "good" switches is getting smaller as more people are buying these up to harvest them (or resell them). Like others have said, the batch is something to look out for if you're looking at NOS (new old stock) versions, and the used versions will all vary and likely require Cherry picking (lol) because they're likely not worn in evenly. Retools are a gamble as well, but at least they're $0.35ea (Novelkeys price) and you're getting 5 pin switches (vs most vints which are 3 pin) so you don't have to play with longer key alignment as much. The term "retools" refers to a specific time in which the tooling for MX Blacks was remade, and was fresh. So they were making really good switches for really cheap. Now retools just really refers to non-vintage mx blacks (which isn't necessarily a good thing imo). There is this new cherry switch as well, the Hyperglide, which is supposed to be very smooth Cherry MX Blacks (among other colors). They are also pretty expensive per switch.
There is something about that cherry sound and feel that is just too good, imo putting retools into a board for a month or so and then lubing, filming, and spring swapping is all you'll need to do to get some really nice feeling switches.