I've actually only have used them for 3 months so far because I haven't had my truck for 3 months. I went on one raptor run with them and the rest has been half highway and city. The ones I had before I did notice a slight improvement but plastic spacers were coming out and started to separate.
I've noticed even more of an improvement over what I had but I also got the whole RXT system. Staying together and no issues. I like how the RXT leafs come with a Add-a-Leaf so you can have 3 different options and can change it around whenever you want. Leave it like it comes, remove a leaf or add another. I added the leaf and with the weight in the back it just soaks up the terrain.
I don't have a real long longevity with them but so far I am extremely pleased. Will put them to their ultimate test when I go to Baja in May for a 1000 miles and 3000 miles of highway.