Metal Halide Bulbs
Metal halide bulbs are better known for their long life, versatility, high efficiency, excellent color rendering, and compact size. They emit an extremely white light, which may sometimes appear bluish. The most striking feature about a metal halide bulb is that, it lasts for about 1000 to 2000 hours.

Comparison
A halogen light bulb has a lesser life span when compared to a metal halide bulb. The halogen light bulb displays a consistent brightness all through its life, but the brightness of the metal halide bulb keeps diminishing over time. (It drops by half after 1000 hours.)