I use all their skin care stuff and foundation. Of course, I get it for cheap, since my mom sells it.
That said, I think you have to be in the right area, with the right type of clientele, in the right part of the country, etc. for Mary Kay to make you ANY money. It's really popular and successful here, and women make tons o' cash on it. But...you have to do tons of the silly house parties too. Which my mom hates. As in, can't stand, won't go to, won't do, hates. So she doesn't make as much money with it, but mainly does it so we can get our stuff at cost.
I don't think it's entirely bad, but it can be misleading and disappointing. And I hate the house parties too!