Completely agree. I'm looking into the SureTest for the voltage drop under load ability as well as the frequency measurement, as well as some of the other test functions that the $2 outlet tester can't do.
I also use it on a lot of ground-loop hum testing since it will identify hot, neutral and ground impedance, as well as predicted voltage drop under 15 and 20 amp loads. I've used it in a parallel test with my big-honking 10kW load bank, and they both agree within a few percent of each other. Between my SureTest Analyzer, Fluke 117 and a NCVT I can measure most anything I need to at any installation or show. Of course, you need to understand what the reading really mean, but being able to tell how stiff of a 20-amp circuit you're plugging into can save a lot of grief when the EDM starts....