I had both the old, silver-nose non-Ai version and the newer Ai type. Both lenses live up to their reputation. While the Ai version was 'better', I never considered it a good lens, let alone an excellent one.
The silver one is plain bad, one of the worse standard zooms for sure. Soft wide open and stopped down one stop, lacks contrast (it was single-coated), lots of distortions.
The Ai version was considerably sharper and more contrasty, but never up to the level of some of the better standard zooms (e.g. the excellent Olympus Zuiko 35-70/3.6, or even the lower-grade S Zuiko 35-70/4). Let's say it's passable unless you do enlargemens. To me, it was still not worth using considering the huge selection of very affordable old glass we have today. I sold both for $10 and $15 respectively.