I have used the drop shackles from Rocky Road Outfitters and they work well for Samurai springs. I have since moved through a bunch of suspension changes and ended up doing the YJ conversion. The drop shackles that Trail Tough sells for that conversion are a bit nicer. Remember that just adding drop shackles don't finish the job, you also have to incorporate a shackle rest to get the job done right.
I like the drop shackles, especialy when doing rough rock gardens and trails that need tons of articulation. I prefer that the tires contact the ground as much as possible. The 'tire in the air' photo shot is great for the magazines, but not as great for the nerves during the more technical trails.
Here is an older, but still very informative article on drop shackles (Rocky Road calls them their 'missing link').
Missing Link