I have been switching between the 'Nike ZoomX Vaporfly Next% 2' and the 'Nike ZoomX Streakfly' on my Tuesday Tempo runs (on road). I have found the following:
> The Streakfly mid-sole is much thinner and as a result I often find I have an ache in my mid-foot the following day from the carbon plate smashing into the underside of my foot. The foam isn't cushioning me as well as in the vaporfly
> I have been able to reach higher speeds more easily in the Vaporfly BUT...have found the lightness of the Streakfly has helped me maintain a higher tempo/'clip' more easily on the longer reps. As a Half Marathon/Marathon specialist, I do notice the weight difference the longer the run goes on.
> I find the more rigid upper of the Streakfly better for my foot. In the past, the lack of rigidness in the Vaporfly upper, especailly over the course of a long run has caused my foot to rock side ot side too much and lead to achiles aches.
Overall I have to say for the 10k and up, the Vaporfly is still the better shoe.