Aside from possible competitors using the samed technology (like www.enclabs.com), it seems the best bet for many types of analysis, but note that it doesn't test for alkalinity or any nitrogen species (ammonia, nitrite, nitrate). Some ions also cannot be detected down to NSW levels (such as iron)
I'm also still not sure what effects bacteria in the sample have on these tests.
I discuss my results and how I interpreted them here: