I use siege towers as a decoy, putting a pair facing the wall sections each side of a gatehouse, while my real assault force mounts far away undefended sections of wall by ladder.
Once I have two or three squads up a ladder I can secure a large section of wall, its arrow towers and a gatehouse. This gives me the advantage when rushing the gate because the enemy will be taking fire from my captured arrow towers and my men on the parapet.
I can generally build two siege towers and four ladders in one turn, perfect for fast sieges.
I don't like siege towers, partly because of the bug, but also because they take an age to load up with a large squad. Of course large walls are too tall for ladders, so I generally use a combination of towers and sap points. The idea here is to contest the walls while my assault force runs in through the breach. But whatever the outcome, this kind of attack is probably going to be bloody.
