Raymondo

Stick to wooden sheds as very easy to put up and more water tight and very easy to repair and secure. Regarding security very easy to secure but remember massive locks look good on the doors but you still have windows and wooden sides..... if there was high chance of theft i would line the inside with sterling board or any other cheap sheeting and this will also insulate further etc, also i would either run a shed alarm or just buy a screamer lock for it.
Metal sheds are made of very thin sheet can slice them open with sharp knife and leak so bad all the joints in mine needed sealing. and soooooooo many pieces to put together..

second hand sheds are fine but will need new roof felt as they get torn when dismantling.......