To me the softer predator compound seems like it lets the tread blocks roll over easier (at least with Krawlers and Hyrax) which actually can hurt grip. The super soft sidewalls also want to roll under easier. My take is that you kinda need stiffer foams with the predator compound to fight that, which isn't necessarily bad as it also can help with turning and sidehilling. That said, I prefer how the Krawlers and Hyrax work in G8, but for the Swampers I like the Predator...they're pretty different tread designs. A friend is about to try the Trenchers in predator compound, I'm real interested in how they do.
As far as foams, the Proline dual stage aren't bad at all IMHO. I use them in some of my tires, and even win comps on them. But I do think CI foams are technically better, its just difficult to know exactly which ones to buy sometimes. I have found that the 'comp cut' inners are preferable simply because they seem to help keep the outer from slipping to the side.