Down are way galvalume metal roofing is cheaper than 30 year asphalt. For the best screw retention, the engineers at the tin roof manufacturers recommend that a solid 5/8 plywood sheathing be used, at least for a house. I think you would be okay using 1x4 lath strips on a utility building, but you may experience some condensation drips.
Installation of tin is fast once you get the first sheet properly aligned with the roof.
Steep pitched tin roofs are scary to walk on compared to asphalt.
