I have a ZeroWater jug. Prior to buying one, I already had a TDS meter, and therefore could compare and check for accuracy.
I have to say, they both report the same thing. 😊
Also, on the ZeroWater tds meter, be careful about not hitting “hold” accidentally. I one day decided to test my meters against my tap water, and the ZeroWater one was reporting Zero… why? It was showing whatever it was on “hold”.