The core difference: privacy or sight lines
Vinyl privacy panels are solid. They block the neighbor's view completely and give you an enclosed room feeling in the back yard. Aluminum is an open picket. It defines the boundary, contains kids and dogs, and leaves the view untouched.
If your lot backs to a pond, common area or tree line, aluminum keeps the reason you bought the lot. If your neighbor's kitchen window looks straight into your patio, vinyl solves a problem aluminum cannot.

