I am not a fan of Yoga. It's hard! I'm not that flexible and some of the positions you have to hold takes a lot of strength. P90X's Yoga is not for the faint of heart; it'll burn calories, strengthen you, and make you more flexible. When you first start, you are cursing at Tony as he breezes through without any problems. You really have to stick with it.
In his book Bring It!, Tony calls Yoga, "The Fountain of Youth". I believe him on that point, I feel invigorated after doing Yoga. He also says after the age of 35 you lose 1% of flexibility per year. By the time you are 65 you are 30% less flexible and are more prone to injury. He recommends at least 15 minutes of Yoga every day.
Need more reasons? Read more on 6 Reasons Yoga's Great for Guys at Fit Corner Network!