I like them. Sometimes the colors can be a bit difficult to read, but I think that's just the male brain, the gf always tells me the colors are obvious. Other then that the only con I can think of Is equipment quality. I've had two of the plastic vials crack on me for no apparent reason. The cardboard and instructions start getting warn out if your doing a lot of testing (as much as I try to keep everything dry I must just be a clutz) other then that I like they're accuracy and simplicity. I got completely sold on the redsea for the quality of the hardware and the price was comparable with the salifert. Can you link to the salifert master kit? (Just out of curiosity,)