Have no personal experience with the Expo rears from AP, but i have run the Long Travel Crawler springs for years and love them, they carry a load well (week of camping gear while on trails) and flex/ride great, durable.
I've run other springs- Downey, superlift, National Spring customs- the AP springs are my favorite all-round performer and shine flexing.
Ive heard lons of people love the OME setups, and the same about sag.
Airbags inflated when you have a load? that might solve your issues.
You should prolly state how much load you plan on carrying and what type of off-roading/on-roading you are planning.
Do you want bolt-on or planning on extended length springs that will give better ride?What shocks will you run?
this would help anyone give you personal opinions on what we think will work for your application. Or do you just want to know what company people like?
Ultimately, you will get a set of springs and tweak them till they do what you want. And they all will work, then fatigue, and get replaced. If your wheeling alot, the couple hundred for springs will come up every 3-5 years anyway, so dont get to tied up in the nuances.