It is the most energy efficient. The two have about the same amount of light output. Annually Lighting Up the Night Sky. The idea of a spectrum. This is a photo of the Moon taken with a small transmission grating placed in front of the camera lens.
White light is made up of many colors.
The spectrum of an incandescent lamp is rather like the spectrum of the Moon, which is actually a spectrum of sunlight reflected from the Moon, of course. The spectral output of a typical fluorescent lamp. The spectral output of a mercury lamp. The spectral output of a high pressure sodium lamp. One can see the spectral output of a wide variety of lighting sources in this photo, including that of low pressure sodium street iights.