I find it funny that the assumption is made that those Ford C-Bushings must allow a lot of flex when most of the Early Bronco guys complain about their lack of flex. That is what led them to first experiment with the Wristed Arms and then later with the extended arms. The longer the radius arms are, the easier job they have of twisting the front axle housing to increase the articulation. Either method increases front articulation, pick your poison.
For true high speed uses the radius arm suffers from a large and undesirable change in Castor angle. It is used because it is strong and lives in desert racing, not because it is the most ideal suspension design. Most are designed with a fair amount of Kinematic Progression, but the first inch or two of compression travel may actually have some regression. No way around that.
If the radius arm length and mounting is chosen carefully and a CV is used at the transfer case, then there is little to no change in the operating angle of the pinion u-joint, and little to no front drive-shaft length delta. Depending on driver style both of these are bonus' that may outweigh the Castor angle issue.
For my own use the radius arm design looks like the simplest solution. I'm not looking for 16" of wheel travel, though I do drive semi-fast in the desert. The added complexity of a simple, non-laterally locating 3 link to get a mild increase in control over the Castor angle doesn't look like it is worth it to me. For others I can see some advantages.
