For me, teak is king. Elegant, sturdy, and withstands harsh weather. New high grade quality sets are very expensive, but I’ve bought several used sets that have sat outside for decades. After a couple weekend days of sanding and re-oiling, they look brand new and are often better quality than expensive sets you can buy today. Granted it’s a bit of a hobby of mine - Never sell, but often gift sets to friends and family. Heck, I’ve got two tables and more chairs than I can count sitting out back waiting to be refinished, that I haven’t got to in over a year.