I installed Bilstein 4600s on my wagon back in 2006 and they still work great, it was my primary tow vehicle until last fall. I just took some Rancho 5000s off my Suburban that were completely shot when I bought it, replaced them with Bilstein 4600s, huge improvement.
Based on how bad the Rancho 5000s were that came off my Suburban, not sure I'd buy Rancho shocks. With 134k miles on the Suburban most likely they were on there much less than 100k miles. My Bilsteins on the wagon have over 90k miles on them and still work great.
I would think since the Ranco 9000s are an upgrade from the 5000s they would be better, plus the adjust-ability has some appeal. I still think I would go with Bilsteins, which I did.