I received my Starrett low-price squares. They are as good (read, as bad) as my previous squares.
They line up perfectly (that is, by eye) with each other and with my existing squares.
My personal test for the accuracy is to use take a verified s4s piece (verified with a trusted square) and then checking all four intersections with the new square, and finally striking a square shoulder around the entire piece. If the end hits the beginning perfectly, I call it good. These both passed.
I suppose I lucked out.
Prashun