An LED is basically a semiconductor that emits light when voltage is passed through it. The LED produces light when electrons in the semiconductor get excited by the passage of voltage through the semiconductor. The technology employed in the production of LED bulbs ensures that it consumes less amount of energy for a much greater output of light. The bulbs do not contain gas like CFLs.
There are massive savings made by just switching to LED light bulbs for the same amount of light generated earlier using the CFLs. Clearly the way to go with lighting is LED, to conserve energy and save considerable amounts of money as well as enhancing the beauty and appearance of structures