I am a big fan of Jet Black as I have it on my e53 (had it for almost 8 years). Sapphire is the "new black" that seems pretty popular. But to me and if you look at the 2 next to each when they are clean Jet Black pops out at you with a mirror refection where as Sapphire is more milky (inherent to it being metallic). When I decide to move to the e70 it will be Jet Black without any hesitation. My $.02.