Inexpensive test kits are better than no test kits, but if there is one kit that is more accurate, then I would opt for it over another. Salifert is more expensive than API, for example, but most any test kit will last for a long period of time, so the higher cost is not as big a deal if you look at using it over a year+ or however long the reagents last.
I don't quite agree that regular testing is not all that important, as testing helps identify trends happening in your tank, but it is a choice each reefer makes, and once your tank is established, may not be required weekly, but I still test my tanks for KH, Magnesium, and Calcium levels every 2-3 weeks.
Whatever test kit you buy, though, hopefully, if it is off by X units, then it will be consistently off by X units so you can still track trends in the tank, even if the reading is not spot on.
I personally like Elos, mainly because of their attention to the accuracy of liquid reagent volume delivery through NIST certification of reagant containers, their use of glass test vials that don't scratch or cloud and retain colors from previous tests that can happen with plastic vials, their handling requirements their Sellers must agree to (temperature controlled storage), and their use of low toxicity reagents vs other test kits (Salifert).
