Nitrate Test Kit Question

Is any one brand of nitrate test kit better than others, or doesn't it
matter?

I ask because one Australian on-line shop says that the Aquasonic kit
"measures the nitrate ion, and not the nitrate nitrogen as some kits do;
essential for accurate testing; range 5ppm to 80 ppm." (Price $13.80)

And a different mob say that the Dupla Nitrate No3 Test Kit is "easily the
BEST test kit on the market". (Price $33.60)

So who do I believe? Thanks.