I have a ZENSAH compression short so that would be my baseline. Both are M but UA seems to have a tighter fit. The fabric/build seems to be of better quality. I use them underneath running shorts. Both wick the sweat away. UA is longer so it has more area for *airing* out the sweat. It is a tighter fit than Zensah. Side note: I was sorely disappointed when I bought another UA long tight in L -- the waist is at least 6" larger -- you can't trust the sizing chart.