So far I have logged almost 100 miles of racing/workouts in the Zoom Fly and almost 50 miles worth of racing/workouts in the Vaporfly 4%. Last week I did an 11 mile progression in the Fly feeling strong, responsive and generally not noticing the shoes. Yesterday, as a comparison, I did a 9.5 mile progression a bit faster in the 4% but it required a lot more effort and just didn’t feel as efficient as in the Flys— not getting “tactile” feedback (for lack of a better term) and felt nowhere near as efficient as I would in traditional racing flats. I was much more aware of the shoes, but it could be expectation effect or something along those lines.
I have both the Zoom Fly and Vaporfy 4% (Flyknit) which I rotate for workouts and races (10k) along with a number of other shoes including Streak 6 / LT3 / LT4, Pegaus Turbo, Kinvara, NB Fresh Foam, various spikes.
Are the 4% *really* only beneficial for marathon? Maybe I need to put more miles on them to get a better sample? Honestly thought they would shine on the days I do more intense volume.