For the question as asked it would depend on if I'm trying to get best performance or a cool piece if history that still performs well. I think the value is almost always used for audio equipment, just how used do you go, and what you consider vintage. Reliability can be better new with electronics, but I think you need to have a plan for good technical support either way. You can hope for the best used, or you have to learn about the manufacturer, design, components reliability, support, and parts availability. As mentioned depends on the type of gear. I just got a tube amp that's 25 years old. It's a great amp for any year built, and not a quality level I could afford new. It's point to point wired and will pretty much be repairable indefinitely by any good tube amp tech with no printed circuit boards in it to go obsolete. Mine's in great condition, but you can be anywhere between like new and a fire hazard, so you have to be more knowledgeable to go vintage, which is a burden. I bought a great used DAC at one-third of new price about 5-10 years old, but I don't think I'd want a vintage DAC, if they exist yet.
Would you spend you money on modest brand new car or rather buy top notch vintage one?
No, this discussion is not about cars, however it's by comparison related to audiophiles. As I see it, most audiophiles don't have the means of affording the top notch, new, improved (maybe), audio gears. So, would you buy moderately priced new or rather buy top notch used equipment for the same money?