The A-word (Armor All) is kind of a dirty word around here...
To be honest, I use ArmorAll Tire foam in the wheel wells, and engine bay rubber, and that's about it.
For your plastic Jeep bumpers, I would use any protectant designed for rubber, vinyl, and plastic. The best is 303 Aerospace protectant, but kind of pricey.
There is also Meguiars Rubber & Vinyl Protectant.
Check the products section of this forum for more info on plastic protectants....