Because of the 2007 Energy Bill, larger tungsten lighting is being eliminated, so now you need an alternative. Most people have not been happy with the compact florescent bulbs offered as an alternative. They burn out faster than they were supposed to and there's a warm-up period after you turn them on. Some of the other problems are poor dimming, shortened bulb life because of high temperatures inside enclosed fixtures, and dissatisfaction with the color of the light.
With LED bulbs. They are safer because there is no mercury content. The life expectancy is approximately 50,000 hours and the energy efficiency is higher than compact fluorescent bulbs and the color temperature is much more controlled. If for some reason you get a bad bulb or it burns out long before it should, most stores, including online, will replace the bulb for free.