i run em on my rig... basically because i changed to a longer leaf and seting up double shackles was much easier than moving the shackle hanger.
Anyway, it makes for monster downtravel. I'm not sure how effective all this is on the trail... probably not (esp. if you're already locked), but it makes for a nice show
1995.5 Isuzu Rodeo - SAS'd and SOA'd, sitting on 36x12.50 TSLs, D44 front, 14bff rear, locked by OX and Detriot, suspensions by Jeep and Chevy, high steer conversion, 5.13 gearing and Teralow in the case.