I just completed my first ride with the Prolights, and they rode great; after riding Specialized carbon fiber shoes for 6-7 years, any new shoe deserves a break-in period, so I don’t yet have any issues to report.
The Prolight SLX saves weight in a variety of ways, but one way is by using three velcro straps and dispensing with the buckle.
Weights here are WITH cleats as actually weighed on my lab-grade scale.
Old shoes: 802g
Giro shoes: 507g = 295g savings (2/3 pound)!
Shoes are also rotating weight, which is even more important than static weight. A lighter shoe is less weight to spin tens of thousands of times on your ride.
Why pay $thousands to save a pound on a bike when you can save 2/3 of a pound on your shoes for not much more than a good pair of cycling shoe costs anyway? It’s a no-brainer value for anyone looking for the lightest total climbing weight.
See my review of the Giro Prolight SLX.