As a hobbiest, I find that the best kits are Lamotte, Elos, Salifert, API, in order of highest quality first.
It depends on what you are testing for. The accuracy of tests are not as important as a trend in your water quality and the behaviour/appearance of your plants and fish.
It can be counter productive to try to chase numbers of so called "perfect" water quality.
It is better to understand why water parameters are constantly changing.