One thing to think about - I switched from mtb to road shoes last year. I figured that I would be able to wear either pair of shoes depending on my mood or what type of riding I was doing. Well it turns out that I actually had to move my saddle because of the difference in the shoes - and its now not entirely comfortable to wear the mtb shoes with the road bike. I don't regret changing the shoes though and I wear the road shoes all of the time now.