As with all styles and colors, metal (Aluminum) frames have made a slight comeback. Popular in the 1980's these frames have come a long way in quality and variety.
No longer do they have that "unfinished" look, they are sophisticated, high quality and clean looking.
While not for every art and framing application they do have their appeal and use in some framing options.
Prices vary and are comparable to wood frames in many instances.