Had a set of those Firestone tire on my 98 American Dream that were install in 2002. I replace them last spring not because of tread ware but because of age and was starting to show crack. Replace them with Michelin only because I could have the Michelin for the same price and a bit softer ride. As for which one is the best tire,
they all have there pro & con, all depend on what type of mileages you do on what condition of road. I'm a truck driver by profession, company have over 50 trucks on the road, guys that do mainly highway run seem to prefer the Michelin. On the other hand guys that mainly do secondary road and job sit delivery like the Firestone better. Michelin will give you a softer ride because the side wall are softer and if your a high miller they will ware quicker. Firestone is a more rugged tire and will carry the load better, stiffer side wall which give you a stiffer ride but more solid
in a shape tune.