the problem is this: most people are used to superlift, skyjacker, etc. these springs are a good price, but are not properly built. i know, because the place we get our material mass produces the majority of their springs for them. their priorities are always cheap springs. a high arch spring will ride softer, all other things being equal. the probelm is they use way thick material (.401, .499) with few leafs. we use .237-.291 material, and have a lot of leafs, they move a lot, have a similar spring rate, and are very progressive. see, you can have one of their springs rated at 200 lb/in, and one of ours with the same rate, and ours will ride much softer. why? its just like a shock with high speed valving vs. low speed. when moving slow, they have the same rate, but when you hit a bump or something where the spring needs to move quickly. thats why ours work. but remember, the rate is actually the same, so things like cornering, etc. arent hindered. all you need is a good quality shock to control the movement, and you end up with a rockcrawler that is actually very street driveable (much better than stock by most accounts), and will blast across the desert with ease.
this is not just theory either. we have set up many successful rockcrawling trucks. the problem is we dont do lots of them, so they just arent seen as much. we do maybe 3-4 k5s a year.
our last one should be in offroad magazine pretty soon, and there are pics i posted of it on rdc.
erik