Recessed-mount fixtures and flush-mount fixtures differ primarily in their installation and appearance. 
Recessed-mount fixtures, often called can lights or downlights, are installed into the ceiling, creating a clean, streamlined look. The housing of the fixture is embedded within the ceiling, with only the trim and bulb visible. This type of fixture is ideal for rooms with low ceilings or where a minimalist aesthetic is desired. Recessed lighting is often used for ambient, task, or accent lighting, providing a modern and unobtrusive illumination solution. Installation can be more complex, often requiring professional assistance, as it involves cutting into the ceiling and ensuring proper insulation and clearance from ceiling joists.
Flush-mount fixtures, on the other hand, are mounted directly against the ceiling surface. They are more visible than recessed fixtures, with the entire fixture, including the base and shade, exposed. Flush mounts are suitable for rooms with standard or low ceilings, as they do not hang down significantly. They are commonly used in bedrooms, hallways, and kitchens, providing general lighting. Installation is generally simpler than recessed fixtures, as they attach directly to the ceiling junction box without the need for cutting into the ceiling.
In summary, recessed-mount fixtures offer a sleek, integrated look with the fixture hidden within the ceiling, while flush-mount fixtures are more prominent and easier to install, sitting directly against the ceiling surface.