i use aquarium pharmaceuticals master test kit.
i think drop tests are suppose to be more accurate than the test strips. i had previously used test strips before i found koko's, and i THINK it might be because on test strips, all the chemicals are on those little pad things, and when you dip it in the water, it is a quick reaction and a quick result in color change. plus when you do the dip tests, some times the water runs down from one test to another test... and i personally think this is kind of sketchy. i mean how can you get a good result if the water is dripping from one to another?
i think most people on koko's would recommend some kind of test tube/drop testing kit... and i know i was recommended AP master test kit when i asked.