Don't judge this shoe after one run. I did some intervals in it on first run and it felt very foreign and not like any other shoe (I've training and racing for 20+ years now at 60). The 2nd run I decided to add a thin additional heel pad to raise the drop a little. Low and behold it was a revelation. I'm naturally forefoot striker, but I do not suggest this shoe for heel strikers (as I would not suggest other high-end racing shoes that don't have prominent heel cushion).
Anyway, the crazy superlight weight and ease at fast pace of dropping the forefoot onto the "sweet spot" just makes this shoe incredible for me. Even when I slowed down, the same drop-down forefoot motion makes it super easy.
The fit is great - not loose and not too tight, and it's easy to get however much lock-down you want. I would say sizing is correct and matches racing shoe size for Adidas/Nike. Great shoes for the right runners. Once I get going in these shoes I don't want to take them off, which is rare for racing shoes.