I have supination (the outside of my feet strikes grounds first) and higher than normal arch. For me, no other shoes fit me better than Specialized because their shoes have a little canter built in (you can see that from the back of the shoes). Shoes that didn't work for me because of that include Sidi, Shimano, Northwave, and Lake (yes, I've tried them). Other shoes that fits ok for me, but not as comfortable as Specialized are Mavic and Fizik (with the footbed). I have not tried Giro, but would be interested to know.
So if you like Specialized for the same reason as I do, you may be wise to stick with it, regardless of the model.