These sheds are well reviewed and I'm happy with mine so far, but there are a few points to mention:
1) It says you only need a screwdriver but a powered driver and drill for some pilot holes is essential
specially through some metal parts (they should have included more pilot holes)
2) Fitting the roof is usually the most tricky part - I think doing it on a hot day helped as it helped to soften
the plastic for adjusting before the screws go in.
3) For the roof, put a screw in one fitted part and then work round and adjust, before all screws go in.
4) The padlockable latch on the 4 by 3 is not really secure and screws are accessible (my old shed had a latch that covers the screws so I suppose you could replace the latch with a more secure one if you wanted) (edited)