If you like it, go for it. Without a doubt it makes the car stand out from other cars as a unique feature.
My opinion though is that it does not make near the difference on a dark color. For lighter colors, such as AW, the car just does not pop like it does with the CF roof. To me, the lines of the car show much better with the contrast of the CF and it creates a completely different look from the 3 series and other cars. For the darker colors, the lines look the same with either roof but you get the nice look up close so it is not as much of a must for me on black.
My dealer's first two Ms were an AW w/moonroof and a JB w/CF. Everyone there agreed that they should have been equipped vice versa. Then seeing an AW / CF,