Why choose a synthetic base oil over a mineral base oil?

Mineral base oils tend to lose their properties more easily, as they have a lower viscosity index (thermal degradation), are more unsaturated (oxidation and deposits), and have more sulfur (emissions) than synthetic base oils.

Related questions:

• Difference between a synthetic lubricant and a mineral lubricant
• Can you change from synthetic to mineral oil?
• Is it worth using a synthetic oil instead of a mineral oil?