Just put in my new airbag suspension. From what I gathered in my search Air Lift has a 1 year warranty while Firestone has a lifetime warranty. I also found out that both of them are probably manufactured by the same company. These were rated at 5,000lbs and can take 100lbs of air.
I went with the Firestone for about $250 from suspension connection. Parts came in about 1 week from time of order. They say it is about 2 hours to install.
The first side took about 1 hour as the instuctions were lacking (not bad, but could have been a little better). Had the assembly together but then had to take a part and put bolts in that were used later. Second side took about 15 min and routing of the hoses and fittings about 20 min.
Added air to the bags and it lifted my truck where it needed to be. This weekend will be the test to see what the differences are when I pull.