Giving it 5 stars as I wasn't able to find any flaws yet and I was able to get good readings every time. Love the fact that it is quick, has a good screen that you can twist to an angle for better view, direct conversion between celsius and fahrenheit. Compared to a simple one found at my local hardware store, this was reading "on the spot"(the other either was broken or it was plain dumb). Compared with the one from my neighbour - got similar readings. I didn't have time to perform a manual test with tubes and whatnot, for pH.