Personally, I prefer the Iridium Silver. They are both close in shade, but the Diamond Silver is definitely blue. One advantage of the Diamond Silver, no one can accuse you of having a silver MB like everyone else. Either choice would be a great choice. Both would be easy to maintain and wouldn't get too hot in the summer. Can you get Diamond Silver with the red leather interior? I love the Iridium Silver with red leather, WOW, what a great combination.