To any and all.
If flex is how you measure the quality of your suspension, then you are only acccounting for one attribute of many. There is more to a quality suspension than just simple flex. Us rock crawlers starting using the 3link design because it doesn't bind. i.e. if you put a johnny joint at each end of every link you will have little to zero bind in the suspension. Regardless of how poor the design is. Its not hard. But there is much more to it than that for over all performance.