This is just my opinion, I have yet to hear a JBL that I personally liked. The mids seem to be pushed back and the bass lacks detail. With that being said there are numerous varieties of JBL, I have heard some models but not all by a long shot. For longevity in vintage speakers I would gravitate to the Klipsch, with the high efficiency the cones move very little which helps them last longer. Many other brands with foam surrounds will most likely be ready for re-coning.

I'm not sure how much you are willing to spend but you might find these interesting www.zuaudio.com you can find the Omens at www.amusicdirect.com for $999.00 a pair. The Zu look like they may give the vintage sound you like while getting a brand new speaker with warranty and opportunity to get your money back if not fully satisfied.

You might also consider used, more recent, bookshelf speakers by higher end brands like B&W or Dynaudio.