How reliable are the Amazon star ratings on these mirrors?

They're a useful real-world signal, especially on listings with thousands of reviews, but Amazon averages are gameable and these particular products lack independent lab testing or specialist-community corroboration. Treat high review counts paired with steady 4.4–4.6 averages as the strongest evidence available here, and weigh recurring complaints (flicker, dim magnified sides, wobbly arms) accordingly.