the boxer brief is my preference. i've tried the under armor 9 inch inseam and they work very well in preventing chaffing, but will smell quite badly after a day or 2. the 9inch inseam also makes it a little hotter than necessary. 6 inch probably is better
icebreaker boxer brief works ok, but the inseam is a little short.
My go to has become the ibex balance boxer. the benefits of wool in terms of smell, and very comfortable and a little more snug than the icebreaker boxer brief. order a size up. i'm a medium in everything and the large is perfect. mediums were way too small.

