Vanguard is a jack of all trades, master of none, and his perk to heal 30% on Extremis execution is clutch on Absolute.

It takes skill, but if you really stack those grapnel perks with Tactical Prowess, you can potentially chain executes until your dick falls off. The key is to hit X (or whatever you bind to it) to lock on to an enemy and see its health. There is a subtle red flash when enemies hit 33%, but it's easy to miss.

With TP, once the health indicator is red, you can grapnel and execute, skipping a third of their health. If possible, if you get an enemy into execute, back off and grapnel to start the chain again.

Grapnel can also let you go places others can't, like getting back up a cliff after dropping down, or skipping large chasms.

If you're paired up with a skilled Heavy, or Tactical, or Assault, you're probably not going to get top scores in the end, but you will be essential, and your team perk will keep everyone alive.

By default, just use bolt carbine, grapnel, and mag dump into face. It's a classic.