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 ...
I put 9000's on my 3500 DRW like 4 years ago and they are a really good shock. Really shines when the truck is loaded heavy. My last two SRW Chevy 3500's ('15 and '18) have Ranchos as part of the Z71 package. I am not sure what series they are but they perform OK. I just put Bilstein 4600 on a Chevy S-10 ZR2. Have not completely rang the truck out but so far I really the Bilsteins in that application. I think either can perform .