I would agree with Foto. Though I have never had overload springs, once they are on, that's it. Until you put a load on them, they're going to be rough riding. With my airbags (I've had them on my previous truck, and now on my new one), when the airbags are deflated (must keep minimum of 5psi in them), there is a noticeable difference in ride, but not uncomfortable by any means. My truck rides just a little rougher than without the airbags, but after a few days, you don't even notice it anymore.
And if you get a wireless air compressor, you can sit in the cab of your truck and add or let air out as needed. No carrying a spare compressor or air tank, and no trips to the station just to add air. Very cool!