It really depends on your personal preference and what is best for your situation. This is particularly true if you have a nice view and don't want anything to block it, which is where glass balustrades are ideal - keeping the view unobstructed whilst still providing a barrier.
These days the widespread use and ready availability of toughened safety glass panels mean an aluminium post and glass balustrade is virtually the same price as the aluminium post and rail (baluster) system, which was previously a lot cheaper. With a slim minimalist handrail on top, these post and glass panel balustrades are one of our most popular barrier solutions with customers.
Aluminium baluster balustrades, with rails fitted between the aluminium posts, are still a great option though, particularly as they can be finished in powder coat colours to match the home's joinery for a cohesive design finish. They are particularly popular as they have such low maintenance demands, only needing a regular wash down with soapy water and rinsing, which can be easily done when homeowners do their regular window cleaning.
Frameless glass balustrades are the ultimate in unobstructed barriers though, with clear toughened safety panels attached to decks by a range of aluminium fittings such as round discs etc. However, as they require a thicker and heavier 12mm or 15mm toughened glass, which is a premium product, they are naturally a more costly option.
Sometimes customers choose a mixture of balustrade styles to cover their bases, with a frameless glass balustrade on the deck where they look out onto a view and an aluminium post and glass balustrade on the side decks where the view is not so important.