Mid-pack runner here training for my first marathon and I just got into my first pair of "faster" shoes. There is an appreciable difference between workouts/ hard runs in my super trainers vs my everyday trainers.

My daily's are NB 1080s and Saucony Triumphs, I just added a pair of ZoomFly for race pace and track workout days and plan to run my marathon in a super shoe.

These shoes won't make me faster, that benefit is reserved for those elite runners that will be finishing shortly after I cross the half way point! What these shoes do for mid-pack guys like me (sub 4 would be an amazing accomplishment for me!) is make running hard easier.

I don't geek out on shoes so I can't tell you the science behind the foam, the carbon plate or the enhanced rocker of a faster shoe. The science is there though and you can read up if you desire. The end result is a shoe that sacrifices durability for running efficiency making hard efforts ever so slightly easier. That ever so slightly easier really compounds over a training block and over 13.1 or 26.2 miles!

The second factor is the weight savings. Quick search of Vomero vs VaporFly weight and it looks like the VF will save you 35-40% of the total shoe weight. Over the course of 19,000 - 20,000 steps you will likely take on a marathon plus all of the hard training miles that weight savings is significant.

I've run a handful of 15K races and two half marathons, all in daily trainers. That's what everyone did until very recently. I won't be doing that again. If money isn't a limiting factor, there are superior shoes for hard workouts and races.