I don't think its fair to pass judgment on a test kit without some attempt at a practical scientific comparison, which we don't have, so I don't want my comments to be taken out of context or in the wrong light but... My "impression" from hundreds of threads in the last couple calendar years is that several members have complained in various ways about their interpet results and its been pointed out, like above, that you don't get as many tests out of them as some other kits. This puts them, in my mind, not as high as the API, Nutrafin or certainly the Saliferts or other high-end kits.
I haven't gone off to dredge up the threads but there are premium quality kits like Saiferts and several others (the others are the names I can't recall) that frequently get mentioned as top-notch. I can't judge the cost comparison or the ease-of-use comparison (although some have mentioned that the Saliferts are not supposed to be harder to use (more bottles/steps etc. is what I'm talking about here))... so these might be well worth considering if the price isn't too much for you.
The API and Nutrafin kits are by far the most frequently mentioned and used here on TFF and seem solidly in the mid-range sort of rough judgement scale about accuracy. I use and prefer the API Freshwater Master Test Kit because it was recommended to me by others here on TFF before me and its always worked out well for me. Many feel the Nutrafin Mini-Master Test Kit is every bit as good, although I've heard a few complain that the way that API switches result colors at "zero ppm" is at least more "satisfying" if not more helpful, as some feel it is. So anyway I usually end up being one of those that recommend the API kit to beginners because so many have used it successfully, but that's not to say a Salifert wouldn't be a better choice.
~~waterdrop~~