A helped a friend put one up, he bought it from a proper shed place. It was super simple but we did not do a concrete slab we used paving tiles. It was great, eventually we put sound proofing in there and he turned it into a mini recording studio. Bigger than the small bedroom lol. It was far from soundproof but it didn't annoy the neighbours.

I remember there was a leak in the roof after building it but we just waited to see where water came in then went crazy with mastik. After a while all the holes were plugged and it was water tight.

For garden use is solid, if expect it to last a decade or more. But the sheet metal was only a couple of mm so if you throw a sharp tool into the side or will dent and possibly rip. The walls were not designed to hang heavy equipment but the roof crossbar seemed solid.