I liked my AEV 3.5" springs, but I hated their Bilsteins - way too stiff. I replaced the Bilsteins with adjustable Rancho RS9000XLs and fell back in love with my Jeep. That is, until the rear AEV springs sagged and lost 1.5" of their ride height. I always thought they were too soft, as my trailer's 115lb tongue weight along with a little bit of gear in back of the Jeep was enough to give the bumpstops a workout (even with the Ranchos at their stiffest setting).
I replaced the sagged springs with Metalcloak's 3.5" springs and now my Jeep is back to its proper ride height, it can handle a couple hundred pounds in back without sagging, and it no longer wallows over large bumps on the freeway. I'm much happier with the suspension performance now, both empty and partially laden (I still haven't taken my Jeep up to its full GVWR).
I hate to admit it, but I used to be a bit of an AEV fanboy. Now that I've been forced to replace two out of three of the main components of their suspension kit (first the shocks and then the springs - the third being the control arm brackets which are still installed) I'd have to recommend going with a similar kit from another brand such as
Metalcloak or
Rancho. I can't vouch for Rancho's springs, but the Metalcloak springs are fantastic. I can't vouch for Metalcloak's shocks, but Rancho's are awesome in all conditions.