I don't know who's bought them and done any hardcore wheeling with them, but they are definitely of use only to the hardcore. Folks who ALREADY have the suspension and body lift to be able to fit 34-35" tires. At 33" and smaller, the stock control arms are already the right length, and you don't have to move the axle rearwards the 1/2" or so you need to fit 35's. Minor benefit is the strength of the arms in this kit, but again, ONLY if you're going rock crawling and have already bent or broken your OEM lower control arm.
Of all the things to prioritize your spending on, get the lifts, get suitable tires to your mission, invest in recovery equipment, wheel it for a couple of years, and on your NEXT upgrade, consider these. A waste of money if you have to ask the question "are they worth it?". If you need 'em, you should already know it and be looking for a vendor.