Personally I use the stall mats. I have had dirt floors and sand floors and I truely prefer the mats when installed proper. Everyone has there own preferance and what works for one won't work for another.
My reason for using the mats is because it is alot more forgiving on the joints, cleaner, stays dryer when used with a good bedding, prevents my horses and foals from eating to much dirt or sand causeing sand colic and also cuts way down on the amonea smell and dust which is alot better for my horses and my lungs. I have COPD so this is pretty important to me or I couldn't be in the barn.
I also love the pellet bedding alot more then shavings. Alot less dust, it's bug and mold resistant, it is very absorbant so all the pee and wet spots are removed also causeing less smell and amonea. The best part of all is I have 3/4 less waste to haul out and compost building up.
Hope this helps
Cathy C