I like the Merrells. I just have a fondess for New Balance because of the fit. I have to try on a pair of Merrells before I fork over $110 plus shipping. They look great.
I have thought about running barefoot on the gravel, but I haven't got to that point. I can't afford random injuries while I'm on call, and the NB100's are fantastic for me now. I don't want to tweak it too much yet. I sprint barefoot when I can on the grass. I'm only worried about the man-made obstacles, really... well, and the fire ants.