I have a Zodiac Futura , its now approaching 12 years old (PVC) its in fantastic condition.
Zodiacs are well built in general ,I know there are problems with the Newer mk2 Futuras which do fall appart It was a glue problem ,and most have started around 4 yrs old.
I have the same one as the one you have seen for sale
Zodiac Futura for SALE
They DO NOTsuffer from the same problems" fall appart" as the MK2 ,and they are made of a higher grade pvc than the cheaper boats and will stand a lot more abuse.
The added advantage Futura have speed tubes , these help it plane and make it a lot smoother ride, the next best thing to a RIB
I do a lot of cruising around the inner hebridies with mine , I would'nt have anything else.
If it is Local to you , Then go and have a look.
If It is "Just a bit rough" , for the money I would bite his hand off !
p.s. 15hp - 2 stroke will work fine.
Hope this helps ..