ExOfficio's underwear was the first to make it's mark as a travel-performance garment. The Give-n-Go is the original, the Sport is the newer softer textile, colors/design it's on the younger side. I prefer the Sport however preference may vary, I use these for every activity: travel, backpacking, long drives/flights, moving furniture...if I'm gonna be sweating and moving, I'm wearing ExO underwear.
Duluth Trading Company recently introduced their synthetic underwear about 5-years ago. After 10+ years of trying, somebody finally found out how to copy ExOfficio's popular underwear. Duluth is using the same textile as ExOffico's Give-n-Go style.
This is a informative and mildly humorous review of several others to consider. Whatever you choose, being able to cut back on clothing helps lessen the weight and clutter. 3-4 are enough for a 2-week trip: wear one, wash one and have a fresh one ready to go.