+1 on cp43's points. It's a good list.
I'll add one more thing about snow. Depending on the roof pitch, snow can slide off slowly. Little hard to describe, but the snow on our roof slides off without falling off for awhile. Meaning it will slide as a sheet and overhang the lip of the roof for a time (and distance) before breaking off and falling. There's no issue except for two possible ones: it can look odd to have this sheet of snow suspended beyond your roof waiting to break off. And depending what's under that overhang of snow (cars? people? pets?) the moment it breaks off can be, um, interesting. My solution was to take a kayak paddle and push up from underneath (carefully!) to slice the overhang off. And be careful if there are plants and/or exterior AC compressor units under where snow will slide off the roof. The snow can be heavy. Ask me how I know.
But all in all, big fan of raised seam metal roofs. Love how they look.