I have installed and removed a number of metal roofs.
No longer a fan unless its standing seam.
Even then, personally I would not have another on my own home.
The typical 3 foot wide "AG" panel with a thousand holes that you hope are sealed with a neoprene washer are good for dog houses and pole barns.
In cold parts of the state, it takes several things for a metal roof to shed, above 32 temps and damn steep helps, however even a 12/12 pitch will not shed reliably unless it accumulates or warms up.
