I always go Matte or Luster (satin) especially if framing. Luster is probably the best, less intrusive on the actual photo.
Gloss was a Kodak invention of the 80s -- as it was a premium that labs charged for. It supposedly looked sharper and had more color. That's not true. It only has more reflection, and prints tended to stick together in a stack.
If framing, go for matted or luster to reduce those reflections.
Silver (not sure if Adorama is confusing this with metal) is a silverish paper best suited for black and whites. Your white point becomes silver and although it looks cool, you lose contrast because of this. I have seen some nice color portraits on it, but also some ones that make people look sick because of the silver white point. You could do that B/W one in silver, I would just exaggerate the contrast before printing.
Metal is the newest thing. I'm not a huge fan of it. I have some samples I got from some metal printers and I was never wowed me enough to justify the expense. It's basically enamel on aluminum, and then covered with a clear coat to seal it. A lot of people use it for HDR (maybe because it matches that gritty industrial look) or nature (greens show up very well).