Maw of Malmortius 3300g 55 AD 36 Mag Res Passive: Up to 39 AD Passive: Up to -400 Mag Damage every minute

Wit's End 2150g 40 AS 30 Mag Res Passive: Each attack does +42 Mag Damage Passive: Up to 25 Mag Resistance

Ultimately Maw of Malmortius costs over 1.5x as much, will do less damage, and will probably cause you to receive more magic damage. I can imagine the benefit of the shield, but it's only useful if it gets used (more likely than not no more than once per battle). For the damage passive to be effective, you have to loose health; we like to stay healthy (based on percentage, not hp lost, making it even worse if you're tanking).

Wit's End will nearly always have a 55 Mag Res uptime in battles ( Infinite Duress will max out the passive). Furthermore, Wit's End gives 40% AS, which stacks with Eternal Thirst as well as it's own passive of +42 magic damage/attack.

You are free to choose what you want, but I would highly recommend sticking with Wit's End. It's generally considered one of the best items for Warwick. You could, however, use both Wit's End and Maw of Malmortius if you find you need even more magic resistance.

I love the builds and i play jungle warwick all the time. I will try the tank one.
Do you think that the maw of malmortius be better then wits end???