A linear spring rate (a low rate at that) gives a nice ride and great flex. But in the turns... lets just say you will probably be the slowest one on the cloverleaf for any given sanity level.
The variable rates tend to be more road friendly. For the same working spring rate (comfort on a flatish road) the variable will handle better. In a turn the outer spring will load up. Since the spring is variable rate, the added load will move to a higher rate and not compress as much. The inner spring will unload, transition to a lower spring rate and not push the body up as much.
There are tons of different spring tunings which can cause vast differences in the performance of the springs. A really stiff linear spring (old school Rancho) will flex so little that it would be rather sporty to drive compared to a soft variable spring.
Now with as much street driving as you state, you probably are not looking for as much of the trail super flexy suspension that 90% of us on the this board are after. Many of use are willing to accept signifient compromises to the streetability of the rig for offroad performance and still consider them very acceptable for street use.
Come Monday, call up a few of the venders and pick there brains as well. Be sure to state a couple of times the amount of street dirving you are after. See what you get htere as well.