If you haven't run in vaporflys you just have to know that it doesn't compare to anything else on the market. It's legitimately that much better than every other racing shoe. It's no contest. I raced a 5k in Zoom Fly flyknits in poor conditions and it was awful. The shoe was too heavy and didn't have the same pop that even the adios gives. It's really only good as a trainer for workouts so you get used to the feel of the plate without wearing out the vaporflys. It also gives you the added training benefit of the extra weight. The flyknit 4% for what it's worth is awful at turning at high speeds.