for me, when I took off my old DRS studs off in the front, I stripped 3 of them. I didnt strip the oem ones when I took them off putting the H&R studs on. The oem ones went back on just fine. That was my experience with them at least.
So to answer the original question, I have both ichiba (v2) and H&R (DRM) spacers installed. I think they look great and so far havent had any issues with them.
So I take back me saying they were of "lower quality" in general (besides those 3 the rest were fine), but at least in my experience, I felt the oem studs were stronger. Am I saying the aftermarket ones are crap? No, most likely I just fvcked up taking them out.