Well, I don't know how much advice this will be but here you go... The SOHC's have a distinct charm amoung motorcycle enthusiasts. Pure simple machines from a bygone era. Although Honda set the precedent for in-line fours back in '69, Kawasaki dropped a bomb with the 1973 DOHC Z-1 900cc. Honda waited until '79 to produce a DOHC.
It really comes down to this:
Is the machine safe?
Is the machine road ready?
Does it fit into your budget?
While a bunch of us cling to our pre '78 Honda CB750's, any 25 year old bike is vintage/classic and may need constant attention. No plug-and-play be any old machine. That being said, take it for a ride and if you feel a kindred spirit, buy it. I always have.