Downlights
Recessed into the ceiling, they almost disappear. They give clean, predictable general light and suit bedrooms, kitchens, passages and offices. The trade-off is that the position is permanent once the ceiling is cut.
Track lights
Fittings sit on a powered track and can be moved, added or re-aimed at any time. That makes track the natural choice for retail, galleries and living rooms where furniture and displays change.
Magnetic track
A slimmer, low-voltage system where modules attach by magnet. One line can carry linear modules for ambient light, grid modules for focus and spots for accent, so a single track can light a whole room.
It can be recessed flush into the ceiling, surface mounted or suspended.
Choosing
If the layout is fixed and you want the ceiling to stay quiet, use downlights. If the space will change, or you want light as a design feature, use track. In a living room, a common answer is cove or downlights for the base and a short magnetic track for everything else.