They each had their place. No doubt coils ride smoother, but may lack in handling when on all 4 corners, (pending rear location and overall weight. Leaf springs are simple, a bit harsher ride but durable. I really like coils up front and leaf rear. The best handling car i ever had was my '70 Firebird Formula 400. You could drive hard and deep into a corner and come out fast. It out handled my '69 Vette, and it had the F-41 suspension.
On farm/ranch 4x4 durability, leaf and solid axel. When Ford made the move on 1/2 tons in 1980, most farmers had to get 3/4 ton to get leaf/solid. After a couple years that coil front would "Bambi" out, and wear all kinds of stuff out. I had a '78 Bronco, (straight axle) and my buddy bought a new '80 Bronco. His road smoother but sashayed down the hiway like an old '60s station wagon. Really goofy with a trailer, my '78 was very stable with a trailer.