When we moved house in October we needed a new small (6×4) shed and after inheriting a plastic one in the old house, went plastic again and obviously needed a base to put it on. Used something very similar to what you’ve linked but from B&Q.
Initial thoughts were that despite all the “easy to use” rubbish, it wasn’t. Was a bit of a ballache to get reasonably flat and throughout I was wishing I’d just got some slabs and sand and created a base from that – it’d have been as much faff and definitely a LOT cheaper.
All that said, now its settled it works. Would I use it again? No – as said, slabs and sand base would have been as good in use and cheaper (we also only have access to the rear garden through the house).