If you do look at the Airlift's, I'll second the "Ultimates". Without that option, they would be pretty much the same as the Firestones. In a pinch, you can run the 5000 Ultimates with no air. Don't try that with any of the others, that I am aware of.
Not sure about your truck, but for my truck the only advantage I saw on the Firestones was that they had two different mounting levels. It is just a second set of holes, but allows a higher or lower ride. I just didn't need that.
As for the ease of installation, they are almost exactly the same installation methods on most trucks.