Choosing the best mountain bike jersey for you depends largely on what style of riding you do. XC jerseys are similar to road jerseys in that they're close fitting and include rear pockets that allow you to carry items like multi-tools and energy bars. Downhill jerseys are lightweight and loose to allow you to wear body armour underneath. A relaxed fit and stylish designs are very common among the best DH jerseys. Enduro and trail riding jerseys come in a variety of styles and can feature aspects of both XC jerseys and DH tops.
Mountain bike jerseys come in a variety of materials, some are breathable and keep you cool on the trial when it's warm. Others provide comfort and protection from the elements when the weather is less favourable. You'll find both short sleeve and long sleeve MTB jerseys at ProBikeKit in a range of styles and designs.