We also have rattan furniture like that (I don't know the exact material), which has been standing outside in all weather for years and still looks good. What bothers me more are the cushions: there are so many of them that they require a lot of storage space. We put them away after each use because they soak up water when it rains and would probably suffer in the long run. This then leads to the consideration of whether you really want to sit on them because you have to put them away afterward...