I am trying to remember the first time I came across their name, was likely in Coral magazine a couple years ago. I have never been a fan of the more complicated test kits for Calcium, Alk, etc.
I never make dramatic changes to my tank, and therefore am not constantly testing anything unless I see a problem. AWT tests just about every parameter I am interested in and tracks it on a graph for easy comparison. They make it super easy with the shipping materials and labels all supplied so I never really looked anywhere else. I buy in lots of 6 now which gives a discount compared to one at a time. I think they have a special right now for a single (multi-parameter) test.