These are great and you really can't beat the price. I have a couple of authentic vintage eames fiberglass shell chair and looking at them side by side I can't tell the difference in shape. I think the mount holes are even the same or close enough to adapt to be interchangeable. Even Herman Miller uses molded plastic these days (instead of fiberglass) now, so I don't see any reason why you would buy one of theirs for $350. Compared to fiberglass, There is a little bit more flex in the back when you lean back, but it's actually kind of nice and doesn't feel flimsy. The only problem is lack of color options. White and black match everything I guess.