I used to sell many of the popular vintage lines (as a young sales pup at lafayette Radio, TEch Hifi, Radio Shack) and have heard pretty much everything since. I remember how the various products sounded back then when new quite well!
Anything "vintage" is old (like me). Old things typically no longer function like new or anything close unless maintained or other wise properly repaired.
My experience with modern repairs of vintage gear has not been good. It often has a short life then you are back where you started or worse.
So..... if you are getting a good deal on a piece that is in good working condition (which is hard to determine), just don’t overpay and it may work out. But at that point, you may end up paying a premium just for vintage bling. Most modern quality gear will outperform most vintage equivalents.
But if you think you must have that "vintage" sound and/or bling, FBOFW, then by all means have at it. It’s what you like that matters and nothing else. You might even luck out and get a good deal!