I don't think you'd go wrong with either, Gary. Both are well thought of, I think. Saliert had an accuracy issue with one of their kits from a bad batch, KH I think, but that was a good while ago. I've never had an issue with any reading that seemed way off base.
I use all Salifert (KH/Ca/Mag). Most Salifert kit directions are like this: put 2 or 4 ml of water in a tube, put a few drops of #1 indicator in, then 1 scoop of
#2 powder, then draw up 1 ml of #3 liquid in a 1 ml syringe. Add #3 drop by drop until the color changes from pink to blue or blue to pink. Then match the volume reading on the syringe to a chart on the instructions to get your reading. Not difficult once you get used to it.