I think the reason I love MAC so much is that it's of quality, but at a much more affordable price than designer makeup.  I have yet to come across a drug store makeup that does what MAC can do.  Granted, I have found makeup of better status, but for quite the price, usually $10+.  I don't have a lot of money to throw around like that, but I do want something that will last throughout the day.  Plus, the colors are fun!  I love their advertisement and their simple packaging.  All the stores I've been in, the cosmetologists have been extremely helpful and friendly [sometimes overbearingly so].