Differences between airbags, helper springs, and upgraded bump stops.

I've been looking at a few lower end suspension options to support the rear when carrying a slide in camper in a long bed 2014 sport. I've so far looked into the Firestone air bags, supersprings, hellwig helper springs, and the sumospring offering. Carrying a constant load of ~8-900 lbs in the bed, I was wondering what would provide the best support and handling returns or if there was any other options I should be looking at around the same price range as the previously mentioned items.