Field of view
At the same focal length and shooting position, APS-C captures a narrower field of view than full frame. The exact crop factor depends on the system.
Depth of field
For equivalent framing and aperture numbers, full frame can produce shallower depth of field. Lighting, focal length and subject distance still matter.
Low light and dynamic range
Sensor generation, processing and exposure all affect performance. Do not assume every full-frame camera outperforms every APS-C camera.
Choose for your kit
Consider lens cost, size, weight and the actual subjects you shoot. Many creators benefit more from the right lens than from a sensor upgrade.