Your right about the personal preference, and I went with the XD.45C in the stainless/green trim. It isn't for everyone, but I like the combination. I went with stainless for rust prevention and less noticable wear on the side of the slide from my Kydex holster. I am perfectly happy shooting with the 4" barrel, but it might be interesting to research some balistics data to see if the extra inch makes a difference performance wise. I would also guess that the extra weight out front might help, but I don't notice any difference when I shoot my friend's 5" 1911. (Maybe not a direct comparison, but it is the only type gun I have shot that had a 5" barrel.)
Hopefully someone with some data and some experience with both models you are asking about can chime in and be more help than I can, really you can't go wrong with any of the choices listed.