I was completely and utterly against two-tone watches, for exactly the reasons brought up above - old man image, car salesman, pretendy rapper, 1980's yuppie etc etc. However, I have seen a few of them on leather straps (or even Jocke's on the blue rubber) and thought they looked rather nice. So I think it's perfectly fine provided it's not on the two-tone bracelet, at which point it becomes rather "too much" in my eyes.
That being said, if you like it, then you like it.