I picked these out at Boston but hadn't really gotten any good miles in on them. I put down a 19-20 mile long run today though and really put them to the test. Good mix of road, dirt, trail, & whatever else SF has to offer. They performed great - could feel the terrain changes so not too much cushion and they had a nice flex to them. Feet are adquately sore as they should be, but knees and joints feel great so they weren't hurting my posture.
Unlike some of the other flats I use the holes in the bottom are designed correctly too - so even with all the terrain changes I rarely picked up a rock, and when I did I could shuffle it out without stopping.
Cons: Light, but not as light as some others. Haven't measured, but it looks like there's slightly more heel to toe differential than I'd prefer.