To be clear right from the start, most of my issues with the Spin Infinity come from the shoe’s fit. With that said, your feet and fit preferences will inevitably be different from mine, so you should go try on the Spin Infinity in person if possible to see whether or not it works for you. Keeping that in mind, I’ll provide some context on how the Spin Infinity fits my fairly narrow, low-volume feet. For reference, I usually prefer shoes with a secure, fairly narrow midfoot / heel, but with enough width in the toe box to provide some room for toe-splay.
Based on my experience with the Spin Infinity so far, its fit seems to be the exact opposite of that description. I have a hard time getting the midfoot / heel cup to cinch down securely, which makes for a pretty sloppy fit — especially on downhills. At the same time, the Spin Infinity’s toe box is about as narrow as they come these days — especially for a long-distance-oriented shoe. The toe box has plenty of volume vertically and is fairly wide at the ball of the foot, but tapers into more of a point than most other similar shoes (e.g. Salomon Ultra Glide, adidas TERREX Speed Ultra, or La Sportiva Akasha II). As a result, my toes get pushed together, especially on downhills when the loose-fitting midfoot / heel allows my feet to slide forward in the shoe.