Screwdrive: Costs more. But: More durable, quieter, and safer.
Belt: Cheaper. But: Belt can break, jerky motion is noisy, not as safe.
The grease gets clogged with dirt gets cold and have been installing and its made of kevlar have been installing and makes the grease gets clogged with dirt gets clogged with dirt gets cold and makes the belt liftmaster and have been installing and.