Please provide a detailed comparison of the features of a Samsung Galaxy S21 and an iPhone 12. Your response should contain at least 10 sentences. Highlight at least 2 sections in your answer with markdown, i.e., *highlighted section*. Include keywords *camera quality*, *battery life*, *operating system*, *price*, *display quality*. At the end of your response, please explicitly add a postscript starting with *P.S.*.
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