Originally Posted by Tequila Joe

I was in between sizes too and thinking along your same lines, originally bought the larger size. I road on my trainer for a bit when I got home and my foot felt like it was rattlin' around inside the shoe. I returned them and got the snug size and am realy glad. They fit like socks now because shoes tend to stretch out a little bit after some use.

Here is a good aritcle on shoe fitting. http://www.bikesportmichigan.com/features/shoes.shtml

BTW: Sidi MTB & Road shoes fit exactly the same. Only you know how snug your mtb shoes are.