Any time I get around 1,100–1,300 lbs of tongue weight, the rear of my truck ends up more than 3+ inches lower than the front. In my opinion, that's not a safe situation.
The RAS completely solved that issue for me. Not only did it level the truck under load, but it also improved the unloaded ride quality. As an added benefit, it virtually eliminated axle wrap and noticeably reduced sway, both when towing and when driving unloaded.
For my setup, the RAS has been one of the best suspension upgrades I've made.