All qualities considered, Cashmere is the better choice in most regards, but Merino holds its own quite well.
Warmth and Comfort
While Cashmere is typically thinner than Merino wool, it is far better at insulating and it provides more warmth. This is understandable when the origin of each is considered, one being the undercoats of goats used for warmth, while the other is from the wool of merino sheep. As for comfort, once again, Cashmere is the better of the two because of its extreme softness and flexible fibers.
When looking at which one is durable, Merino fares much better in general. Higher quality Cashmere can sometimes overtake Merino wool in this regard, but generally speaking Merino lasts longer. The fibers withstand pressure and wear better, and their flexibility makes them able to adapt to movement easily. Both are antimicrobial and cashmere is the better option for those who are prone to allergies, as lanolin can cause issues in this regard.
In this regard, Merino is the better option because it comes in a more affordable price, and the options are various when considering types of garments, construction and use. Cashmere is quite expensive because of the reasons we mentioned previously. However, the finer the fiber of both Merino and Cashmere, the higher the grade and the pricier the garment.