The Gulf Air 1-11s were second hand and, as with cars, you don't know what you have until you start using it.
A lot of 1-11 operators achieved very high dispatch reliablity with many above 99%.
At BCAL there was a notice board, (by the canteen IIRC), that showed the figures for the last week or month. The 1-11s were always 98 or 99 % and the fleet was well used in the early 80s when I was there.