I really like this shoe, go up a half size! I have worn the standard Zoom Fly, and the Zoom Fly Flyknit as well. I like this one the best. It is the lightest of the three. The overall look of the shoe to me, its ugly. Terrible. But I care about how it runs. The standard Zoom Fly was ok, just felt like a lot of shoe. This upper is much better and lighter. I also ran in the Zoom Fly Flyknit, it has the flyknit upper and instead of lunar it has react soles with the carbon plate. I can see why they did this, this shoe is stiff, stiff, stiff. They take a little breaking in. But the Flyknit is heavier and has no structure, it feels like a brick on your feet. This shoe is for fast days, it wants to go fast! I would grab some Pegasus for slow days, and break this out for tempo runs, repeats, and race day.