Google AdWords is an incredible marketing product for businesses. I think it's such an important tool for any business or individual with a product or service they are trying to sell.
One of our clients built his entire business from Google AdWords and pay-per-click advertising. He did not spend money in any other marketing channels. Only pay-per-click. His business grew like crazy, and was very profitable.
Ultimately, AdWords is so powerful because you are targeting your customers specifically. Your ads are being served according to their search terms. This is not "shotgun" advertising. This is pin-point, right-on-the-money advertising, that every serious business should be using.