It also moves the shocks up out of harm's way. I remember when I had the SUA and would scrape the dial off of my Rancho 9000 shocks on a regular basis. With a SOA, you should be able to run 35" tires. They might rub on the front edge of the fender, but that is easily remedied by pushing the edge in a little.
If you are going to SOA the rear only, then you would need 5-6" of front suspension lift to level it out. With all the modifications over the years to my Explorer, I really have no idea how much lift it has. I think the rear is around 6" higher than stock, front is probably 8-10" with the SAS.
I have had several suspension configurations over the past 24 years owning the Explorer;
Rancho 2.5" lift
Superlift 4" SUA
Superlift 5.5 SOA
Mixed parts 5.5"-ish with the Superlift Superrunner steering
Current is Franken leafs made from 2 sets of Explorer springs to get the height I wanted, with dual shocks to help with body roll. Rear is still set up this way. Its a little stiff and I am planning on a custom leaf pack from National Spring in the near future.
Front is SAS HP D44 with 14" coil over shocks and Duff radius arms.
If I had to do it all over again, I would have skipped right to the SAS and SOA. The SAS is super stable in the twisty stuff, and with the coil over shocks and Duff arms, I feel it will run with most TTB's at speed.