Hemp and Linen fabrics have many of the same positive qualities - such as being temperature regulating, lower environmental impact compared to conventional cotton, and antimicrobial properties. However, choosing a baby carrier fabric is a lot like choosing a pair of jeans - some just fit better for different people. In particular, while both fabrics are strong and soften over time, Tula Hemp has a softer hand-feel right out of the box and the appearance of the colors is more saturated, whereas Linen is has a more subdued color and more intricate herringbone woven texture.
We always recommend choosing a carrier you'll love wearing because that's part of the joy of babywearing.