Softshells are primarily a shell: an outer layer that can on occasion be worn as insulation. Made from fabrics with a high degree of stretch, softshells offer unrestricted mobility in addition to the weather-shedding and wind-resistant properties of a tightly woven smooth outer finish. They are designed to be used during exertion, in conditions that do not require full wet weather protection or significant insulation.
Hardfleece is primarily a fleece: an insulated mid layer that can on occasion be worn as an outer layer. The advantage of having a smooth outer surface is the durability this provides, in addition to the texture's natural resistance to snags and tears. Hardfleece is less air permeable than traditional fleece, but more durable, and often with a greater degree of insulation. While they may be worn as an outer layer, the fabrics do not provide the moisture resistance of a softshell, nor do they have stretch comfort.
Softshells and hardfleece are not intended to protect against extremely wet conditions. For fully waterproof weather and storm protection, a GORE-TEX® outer shell is essential.