How good of a tank would a Lancer be in comparison to other classes, like Marauder or Gladiator?

Obviously, a Lancer couldn't compete against a Gladiator in straight-up damage reduction, due to the lack of a shield, but certain things like Speed/Life Surge giving a small, constant HP recovery, or Diversion allowing the Lancer to fully mitigate certain enemy skills can give an advantage. In addition, Speed Surge/Life Surge can be used as a sort of AOE taunt, since they seem to give a massive amount of aggro for whatever reason.

Let's have a well-mannered, civilized discussion on the merits of having a Lancer be the tank for a party, compared to a Gladiator, Marauder, or even Pugilist.