The best part? After 20, 30, 40 years, they'll sound even better! I can tell you that because I have 20+ year old New Beat hats and Medium Ride, 25+ year old 18" Medium Crash, and a 35+ year old 17" Medium Crash!
That 17 is usually my favorite crash of everything I own. Just the perfect example of what "crash" should sound like.
That said, they will sound far different than what you're used to. My band's drummer got a kit a few years ago outfitted with newer Zil As... and I hated the sound. Hated, that is, until we got out and started gigging with them.
Great, versatile cymbals, and they only get better with age. Just don't EVER EVER EVER polish 'em!