When shopping for a set in the past (also while doing a lot of other front end work) I was specifically looking for other options outside of Bilsteins that offered a lifetime warranty. Only other aftermarket option (at the time at least) was Rancho 9000 series, which had adjustable knobs right on the shocks to increase or decrease resistance. Settings 1-9, where setting 5 was the 'stock equivalent'. They are also compatible with the Rancho "My Ride" system (which unfortunately was complete crap).
I went and bought them at my local 4 wheel parts using the part #s they came up within their system. I was also getting a new set of tires at the time so I just had my tire shop (NOT 4 wheel parts, but my local mom&pop shop) install them. 4 wheel parts sold me the wrong parts, but thankfully my tire shop caught it and got me the right ones. Ended up losing out on my rebate because of it (tire shop was not an authorized Rancho distributor) which sucked, but better than having the wrong ones...forever. If you go this route, call Rancho to confirm your part #s and then shop around.
The only adjustments I crawl under and make are to the rears when I'm towing heavy (I dial them up to 9) and there is DEFINITELY an improvement in bounce when cruising across transitions on the highway.
I've read (in forums) praises to Rancho Warranty conditions too, something as minimal as the adjustment knob breaking off gets an exchange no problem. No registration required at the time of purchase as long as you can provide proof of purchase when you are trying to exchange (a VERY important detail to pay attention to when you're buying something for its warranty)