In most cases, climbing shoes come with either leather or synthetic upper part. And although every material has its pros and cons, leather is considerably easier to maintain as opposed to synthetic. They are easy to clean with a simple wipe and smell fresher for a longer period of time. This being said, the leather climbing shoes that are unlined tend to stretch out a whole lot and their dye color can easily transfer to your feet when sweating. Synthetic shoes, on the other hand, will do neither of the aforementioned. On top of that, they are the number one choice of vegans and merely those living a conscious eco-friendly lifestyle. You do the picking.