I have a concrete aisle and ended up covering it with rubber mats. If I was starting from scratch, I’d do a concrete aisle with a lip or edge that mats fit into. My mats do shift because of the way my aisle is but I still love having the entire aisle done in rubber mats. Much safer and quieter than concrete.
The rubber mats I used have a raised pattern and I have never had a horse slip on them.
Before I had the rubber mats, I had a loose horse trot into the barn aisle, slip and fall - she fractured her coffin bone. I didn’t like the concrete prior to that and bought rubber mats as soon as I could after that accident.