I would back up comments re. the quality of the old Super Takumar lenses for the Pentax Spotmatic, mine were superb. The Nikon found favour with pros, not because of lens quality (although their lenses have always been good) but because they were the first to produce a total camera system, with rugged bodies, motordrives and every accessory you could need. The top priority for pros in those days was utter reliability in hostile conditions, and Nikon provided this.

Purely in terms of lens quality, my vote would go to early Pentax and Minolta lenses.