A good horse will give you100% a good mule will only give you 90 , he keeps 10% for himself. I was at a branding many years ago. I was riding a bridle mule,not mine. A friend asked how I liked that $5000 mule, I told home about like a $1500 horse. 90% of the big pack strings in the high Sierras are led by a horse. I asked a packer why that was, he said the mules would follow a horse anywhere and a good horse would give you all he had where a good mule wouldn't