If you want folks to take a full skewer for themselves, wooden skewers, soaked for 30 minutes (so they don’t burn on the grill) is a nice option, but when I have a big crowd, or I want folks to be able to more easily pick and choose what they want, I remove the meats, fruit and veggies into bowls and serve with tongs.  I do find that, in general, metal skewers are easier to turn on the grill and don’t give you splinters when skewering… which I seem to get every time.