I bought a billy oh pent metal shed for my old house, as I needed an odd size (might have been 7×5 actually) and a door on the short side. I stupidly put it on a plank of ply as a floor, so after 5 years had to remove the whole shed from the floor, rip up the (rotten) ply and put it back. It held up surprisingly well to the movement – in the end I just bolted it down (with standard rawlplugs) to the knackered crazy paving underneath. 3 years later (total 8 years) its still up, although it was placed in a very sheltered spot. Didn’t seem like it’d survive very well to a security ‘attack’, nor really strong winds, but otherwise good, if a little damp inside when it had the floor (on paving slabs it was much better). didn’t look very nice (compared to a wooden shed)