thanks for the response guys..
from info gathered on the search, the HD leaves are softer (137lbs/") until you hit the overload (257lbs/"), so they should ride better than the LD (148lbs/"), and be able to haul more weight. However, i like to go rock crawling, so i'm not sure if the overload would hinder flex.
i spoke to ARB, and the guy told me they would both net around the same lift, 2.5"+, but the light duty will be a bit stiffer empty. he also said the HD's overload is somewhat straight and there's a possibility of getting hung up on something.
i really only have my 60lb spare in back, and when i go camping, mite carry 150-200 lbs. tow a trailer twice a year..