I like this product with a few caveats. The testing is really operator friendly, tracks results on your iPhone or iPad, that is pretty darn cool. Oh and the test strips are about 10-20 cents each, not a throw away but ok. My experience has been the alkalinity test is as consistent with my hanna checker. No complaints about the calcium test. The nitrate lower limit is 15ppm, phosphate is .09 ppm, and the magnesium test is not really possible because of upper limits of total hardness test but they hope to have all of those resolved maybe by year end. Also, you can test and walk away and the results do not vanish like on most other kits or testers. So its not perfect but pretty cool and when they correct some of the issues addressed this should be the cat's meow for now. At least until someone comes up with a better device for testing.
And yes for the time being, I cross check my results with my hanna checkers (Alk and ULR phosphorous), API (nitrate), Salifert (Nitrate) and Red Sea pro test kits (Nitrate, phosphate, dKh, CA and Mag) but hopefully all of those will go soon enough to the back of the drawer and I'll be using this photometer for all my testing until or unless something better comes along.
Ultimately the key to testing is reliability, consistency, accuracy, operator friendliness and cost.