The Rucker 4.0 appears to have a few changes: extra padding on the top of the plate, velcro closures on the internal flap pockets, extra d-rings inside the bag, and no slant pocket on the front. This is all done to make for less breakage when slamming the bag around — everything else seems to be the same as the 3.0 model. The Multicam Tropic model does come with a matching hip belt, and appears to be running the camo pattern horizontal — which would be great if it proves true during shipping.
The Rucker Long Range is completely new. It’s a Rucker 3.0 design, on the GR2 platform (so you still get zipper pockets and the front pocket, no extra d-rings, but the sleeve does seem more padded). These come in 33L and 39L for $245/$255 — that’s a hell of a deal for the GR2 platform. They have the slick material against your body and the lumbar support — I bet they feel killer to ruck with, or use in general. GORUCK has been talking about this model for a while now, and it should be great for those who find the 25L stuffed with a plate and hydration bladder (which it is tight).