FWIW, I installed the HD, it was better then what I had on (oem). I think the OEM were at 60K-70K miles before I replaced them. I installed the HD 3 yrs ago, truck is now at 115K miles. to me its gotten rough even before i lifted the truck. BUT my parents say the ride its better since I lifted the truck. LOL..i guess it depends where you sit. either way im replacing them.
As for the rear, im looking to go down the same path as Bob once he gets it all square away.