What I use is not MAC *gasp* but it's a staple, I think it works well because it isn't thick, I don't like most concealers for under the eye b/c they are too thick and crease/cake up. Benefit's boi-ing has heavy coverage without being "heavy." And also their lemon-aid works great too, it's the whisper-light texture with awesome coverage I like. If you want to try it, go to your nearest sephora and swipe them with a qtip and take it home, try it there.