I’m predisposed towards monochromatic images . . . they seem to evoke more of the emotional qualities, the soul, of the photo’s subject.  That said, I recognize that some subjects scream out to be reflected in all their resplendent color – flowers for instance (though, even they lend themselves to b/w, where their “veins” and textures alone convey the amazing artistry of Nature’s hand.)  And, just like with everything else in life, there are subjects that are indifferent to being captured in either mode. For example, this little guy could easily be enjoyed in b/w, but I liked the green on the pier and the muted rusty reds of the bulwark behind him. (I wonder if he ever figured out what he was looking at . . . )