The Brooks Dyad 4 feels awesome, it's definitely an improvement on the third model. It has a great breathable upper, really really nice. Experienced Dyad runners may also note that your foot sits lower to the ground in this model. This may be alarming at first, but it's not a bad change, especially if you take them out on the trails. The reason for this new fit may be for the updated ultimate sockliner insert. Regardless, the Dyad is still THE SHOE for flat footed neutral runners.