I'm a huge Merino wool undergarment fan. Wool is naturally water resistant, fire resistant, air permeable, and slightly antibacterial. Wool fiber exteriors are hydrophobic (repel water) and the interior of the wool fiber is hygroscopic (attracts water), this is one reason wool can get weight while still retaining it's heat. The most important one when it comes to boxer is probably the antibacterial and the fact it will generally not retain smells, at least not to the level of cotton or synthetics.

The boxers themselves are well made and true to size for me. One important thing to note when it comes to Merino wool is that is takes more care than other material. It won't hold up in the same way as cotton or synthetics. So if you just throw it in with regular clothing to wash and dry, they live span of the clothing will give you less than stellar results. If you are willing to take care of it properly though it will last quite awhile and serve better than any cotton or synthetic.