I have crank bro Candy's on my road bike and I like wearing the mtb shoes. I've never used road pedals so i'm not sure about the comparison, but I like the metal contact bits of the candy pedals/ crank bros system since its hardier, withstands rougher use.

Also I feel safer about walking in my shoes when I ride on my own and I need to stop anywhere on the roadside/ if its raining etc. I've seen people slip and fall quite nastily. I've slipped on the pedals myself from wet grass (waiting at a traffic stop) it's quite painful, and if its a bad one, can be really dangerous, being on the road and all.