Slab is probably simplest. They use a lot of concrete which I would have had to take through the house so I put my office/shed on a grid of 12 concrete piers which the base frame sits on. Good for air flow too.
Yeah I was toying with concrete piers as they'll use less material and thus cost less. But I guess you need thicker floor joists so that might cancel out the money saving.
What's the best base for a shed?
Concrete slab?
I'm looking to build something 4 x 2.5m