Bilstiens are hands down one of the best out there. If your willing to spend the money go with them.
I dont have the money to spend on bilstiens so i went with procomp es9000 (+2" in the front and the ride with the leveling kit is much better, stock length in the rear). Most of the 9000 series shocks are pretty much the same. I went with the procomp because they are nitrogen charged. I have two friends that have BDS 5500 on there HDs and both only complaint is that the freeze up in cold temps.
I have around 4500 miles on the ES9000 and am really happy with them and the ride so far. I pulled a 5000 lb trailer with zero squat