I have had airlifts in one of my vehicles and really liked them while they worked, they have split the bags several times on me and needed replacement. The bags are under warranty for life but the labor is expensive each time.
I am currently having an extra leaf added to my Sierra, literally on the lift at the mechanics shop right now. This is my first time with adding an extra leaf so I've got my fingers crossed.
The airbags worked great, but I stopped trusting them due to how fragile they seemed. My airlifts were inside a coil spring type suspension, so perhaps the models for leaf spring suspensions are more robust.