Bottom line on late-model Rangers and Explorers, a little lift is cheap (TT and shackles) and a lotta lift is expensive. Personally I'm not a fan of body lifts.
The Superlift is a good kit, however it does lower the front crossmember and torsion bars, so it does negate some of the lift you get. Okay for looks, general off-roading, and sand/dirt/mud. Not so good for rock crawling because the torsion bars are exposed big time. The RCD kit uses coil-over shocks and eliminates the torison bars, so it's better for rocks.