I have them also. Used them a few months then went back to the ordinary Weber hinged grate. I didn't really like that the grate direction wasn't uniform among the quarters. Who would design such a thing? You need to put your steak right on the quarter to get uniform grill marks on the entire steak.
They are sitting in my shed now all rusted up. Keep thinking one day I'll refinish them, only because I have them.
After having them, I wouldn't buy them again. Grill marks are over rated IMO. Go for taste!