I guess I am in the camp of being wary of GSC. Since coming back to the hobby after a few years away I have purchased perhaps 10 coins from them. Half were Buffalos that I feel I did very well on but I do have a few that I just received that are being returned. Those, mostly larger coins like Walking Liberty's, Standing Liberty's and Commemoratives were scratched. In all cases, they otherwise would have been fine aside for what appears to be more recent scratches. I suspect they cracked them out after they had been rejected. In all cases, I did not miss these in the photos rather their photos concealed the scratch. All were "superb gem" listings but they are not something I want with a glaring fresh scratch that does not even take magnification to see.
It seems that with the smaller coins, being able to enlarge images on my phone, I can spot nearly hidden defects but on the large coins glaring defects seem to be hidden. Lesson learned I guess but a couple of the Buffalos ended up being very nice and nearly defect free.