I'd have to disagree, Mundo's damage lategame is considerably lower than other Juggernauts like Darius or Illaoi. Mundo is decent overall after his recent buff, but he falls off late because his damage just doesn't scale well. He goes where he pleases, but it doesn't really matter much since it takes him so long to kill a squishy. He lacks the pure damage most Juggernauts have and the hard CC that true tanks have.

Quick comparison:

Mundo's got around 130 DPS aura from W and Sunfire, 230-300 AD on his autos with AS of maybe 0.9/second, and a 25% current HP cleaver skill shot on a 3.2-3.6 second CD, depending on CDR. Assuming he can stick to you, he'll do maybe 400-500 DPS to a squishy.

If Darius gets his passive rolling by attacking the enemy tank line when they engage, he has ~400 AD, an auto attack reset on a 3 second CD, an AOE nuke doing around 700 dmg every 3 seconds, and a passive burn doing 100 DPS over 5 seconds on anyone he autos or Qs. Plus a 1K true damage nuke that resets on kill, and all his physical damage is ignoring about half the targets' armor from E passive and Cleaver. Once his passive is up, he doesn't need to stick to a squishy to kill them, he just has to get his passive on them with a quick AA-W or Q, then dunk them. And then he can move on and do that to the next champ. The only way Darius will do less damage than a Mundo is if he can't stick to the enemy tank line and get his passive stacked, which either means he's against a really kite-y comp, or being played wrong.