I have factory air suspension on my old Lexus GX470 (2004). Original bags were replaced preventatively in 2023, and I am actually sitting on a replacement compressor and a set of leveling sensors that are going in this weekend.
All over the internet people complain that the system is unreliable. That's just not the case. Any mechanical system that can give 19-20 trouble free years of operation with zero maintenance is pretty good in my books. Use good quality part and check your fittings (soap: no bubbles, no troubles). If the system is self regulating, it will typically cycle the compressor in the morning when the air inside the air spring is cold. They may also loose a tiny bit of air from the fittings. Keeper bags are a little more basic, but would be really valuable when towing with a mid size SUV/pickup just to level the tow vehicle - combine with something like a milwaukee inflator pump, and you can really dial in the ride height fast and easy.
I really like mine - there are a lot of mid sized SUVs that seem to be designed for zero additional load and have the nastiest squat. Ever see a new Nissan pathfinder tow a trailer or fully loaded with passengers/gear - looks awful. My GX tows dead level, and I can adjust the height a few inches in either direction which is really useful to prevent bottoming out the trailer when you are dealing with low speed maneuvering and abrupt grade transitions.
. I've had bags on the past three trucks and no leaks. I've had them on for 5+ years on the current truck. No leaks.
