My father bought his pair of AR-3a's in January of 1969. Throughout my entire childhood that sound became my reference point in audio. The setup in those days was anything but optimal - Pioneer 25 wpc receiver, speakers against the wall on carpeted floor, lamp cord for speaker wire, Dual turntable with who knows what cartridge, etc. He eventually put them up in the original boxes due the pots being so bad.
A couple of years ago I was putting together a surround sound system and needed two more speakers. I went to get them and only one was functional. I had the one speaker playing in the background as I was working on the other parts of the system. As I was walking away, I heard something unbelievable that stopped me in my tracks. The one speaker sounded really, really good. I realized that they needed saving because of their potential. At that point, I knew little to nothing about AR or acoustic suspension.
Through this forum, I was able to learn and eventually restore those speakers (caps, rebuilt tweeters, and Kent's potentiometers). They sound amazing and was able to give them back to my father with a more capable amp that does them justice.
I now have a set of LST's that I am currently working on and acquiring the appropriate components to power those beasts.
In response to the original question - I vote for the vintage because they have a sound I haven't been able to find new, but that may be because I grew up on them.