I actually tried this in the store and although my shoe size is 8, it was tight, so I ordered a half size up and it's ok. Although one foot is a little loose in it. It is very comfortable for walking, but when I use it on the elliptical my feet slide in it (the pedals on the machine do not tilt and are parallel to the ground) and I wear athletic socks which are totally fine in my other shoes.
The other thing is that the fabric inside where my little toe goes is totally worn out and gone and that is strange because with this brand I didn't expect it and in such a short time too. It is bothering me as if there is someyhing in my shoe. Also my second toe  got hard tissue on its side since wearing this so if I could I would return it. It feels comfortable but has its hidden problems.