Comfortable and helpful. Threw it into the wash before my first wear and it held up great with no tears or threads falling apart. Then wore it climbing. Didn't build up a sweat, but it was very comfortable to wear. It fit to size and I didn't have to worry about adjusting or anything! The pocket in the back was able to store my iPhone XR. Although it fit in there diagonally, there was still plenty of space to store other personal items: small wallet, keys, chapstick, mask, etc. Overall, great and looking forward to wearing this while on a run!