Yeah look into it but then things add up like a compressor and wiring the thing as that's the only way to go with those.
FWIW, anyone I've known who's had air bags on their truck didn't have a permanently installed compressor. They just used an air hose from the shop air compressor or a little cigarette lighter type. They only changed the pressure when they were carrying something heavy and wanted to level the truck, so it's not like they'd use it every day. Even then, it only took a few minutes.
I want simple and after reading about these, they sound like something that will do the job. There's suppose to be an 1 inch gap between spring and these things so normal everyday driving isn't affected by them. Sounds okay to me.
They definitely look like they've got some good points and seem pretty indestructable. If they work like I think they do, then they'd definitely help the suspension when it's heavily loaded. But, as you say, there's that 1" gap, so the springs will sag by at least that much before they take effect, and your truck won't be level. With airbags, you just adjust the pressure to where you like it and make it level when needed. With the rubber springs, you'll also have to guess the load to install the right ones, and if it's not right you're stuck with it, since they're not adjustable.
The other drawback, I think, if you do any offroading, is that you'd loose flex in the rear end, unless you unbolted them.