I feel SGC standards have stayed around the same but I agree that the grading of corners has tightened up nicely (a bit stricter). SGC is still my choice of graders, even before they advertised.
That said, I don't always agree with them and we can agree to disagree on some things. But they and BVG are my graders of choice. I don't generally have high grade material but if I did I would have to look at PSA; for their registry.