Pentax Super Takumar lenses rendered superb results for me, especially the M42 screw mount SMC's. That doesn't discount Nikon, Leica, or Canon, but it was my preference. I still use an ES-II, and the 70's era lenses do fine. I also preferred Kodachrome, because the others tended to be a bit cool for my tastes, and folks liked the warmth of projected Kodachrome. Later on I tried Fujichrome, found it was too green-biased, and found that Ektachrome was a bit too blue-biased. It didn't make any difference the brand of camera or lens, but results relied instead on the color bias of the film.
I've scanned several thousand 35mm slides, and my original suspicions have held. Fuji is green-biased, Kodachrome red-biased, and Ektachrome blue biased. The most neutral seems to have been Agfachrome, though it wasn't my favorite at the time.