I mentioned to a mechanic friend that I was looking to put some Bilsteins on my truck and he sort of pooh-poohed them and recommended Ranchos. Bilsteins seem to always get the nod here, just looking ...
They both offer lifetime guaranties but the Rancho 9000 series is adjustable and the Blistein 4600 is fixed. I went with the Rancho so I could control ride comfort whether loaded or empty. If I was always loaded, I would have chosen the less expensive Blistein.