Option 1: Aluminum Pickets
Aluminum picket railings are the workhorse of the deck world. They are incredibly durable, relatively affordable, and require almost no maintenance beyond an annual wash with soapy water. In terms of design, they offer a traditional, defined boundary.
Lower cost, excellent airflow (breezes pass right through), zero glass cleaning required, defines the space clearly.
The pickets (vertical bars) obstruct the view, especially when sitting down. Can feel 'cage-like' on small decks.