I use the dip sticks more often than the test tube style of tests. I have used both at the same time often enough to know how to compare the results.
API: Good. Dated so I know how old they are.
Red Sea Fe: Never got a color that matched the chart.
Jungle 5-way or 6-way test strips: Well, I know what the colors mean when they do not match the chart.
Jungle Ammonia and Chlorine/chloramine test strips: Good.
Spa and pool tests: These work, too.