Sean, regarding the big foam bottoms of the Hokas. When I first tried them on in the store the saleswoman grabbed a bunch of metal pieces of the shelf (big ball bearings, a metal coat hook, some big bolts) and dropped them on the hard floor. She said, "Step on them." The foam soaked them up like they weren't even there! Now, what does this mean on the trail? It means that all those little nagging sharp rocks you normally avoid on the trail are non issues. Just run right over them! Normally, when I encounter skree or rubble on a trail, I walk over it, because I don't want to wear out my feet. With Hoka's I just keep on going. Where Hoka's really shine is the downhills as you get a spared a lot of the pain.
I have two small problems with Hoka trail shoes. One, is that they feel a little sloppy in the uppers and until you get used to them, you feel like you are going to roll on the edge between the upper and the sole. Over time, this goes away. Second, you are a little higher than other trail shoes. For some reason this changes your stride slightly forcing you to engage muscles differently, particularly on uphills. As you adapt, over time, this feeling goes away.