Diablo III- Skills Article XIV: The Barbarian, Might Skill- Revenge

Revenge: Has a 15% chance to become active for a short time when you are hit.  Using this skill deactivates it again.  Deals 220% weapon damage to all enemies in melee, and heals you by 5% of your maximum Life for each enemy you hit.

Revenge is a very odd skill, that is best defined by one word- comeback.  If you find yourself hanging on by the slightest sliver in your Life Orb at the end of a lot of combats, chances are you should be using this skill.  Not only will it give you a better chance in such fights, it’ll patch you up so you can keep on kicking.  The really difficult thing about Revenge is that it’s entirely luck-based- you could find that it’s just not available when you want it.  When it does pop up, though, you’re going to love it all to pieces.  Or is that hack your enemies all to pieces?

Vengeance is Mine: Has a 15% chance to become active for a short time when you are hit.  Using this skill deactivates it again.  Deals 220% weapon damage to all enemies in melee, and heals you by 8% of your maximum Life -and- gives you 5 Fury for each enemy you hit.

Vengeance Is Mine is an excellent rune for people fond of Whirlwind and Rend, particularly with Wrenching Smash or Call of Arreat to increase the number of enemies in range when you use Revenge.  Pitting this together with either of those runes will let you refill your Fury almost-completely or even completely at a crucial moment, as well as ensuring you start your comeback with a lot more Life than you had a moment ago.  This turns Revenge into an excellent emergency button when it becomes active if you’re being dogpiled.

Best Served Cold: Has a 15% chance to become active for a short time when you are hit.  Using this skill deactivates it again.  Deals 220% weapon damage to all enemies in melee, and heals you by 5% of your maximum Life for each enemy you hit.  Increases your Critical chance by 10% for 12 seconds.

Curiously misnamed given that it in no way delays your use of Revenge, Best Served Cold is the premier Revenge option for critical hit monkeys, drastically increasing your critical rate when you use Revenge.  This offers some really impressive critical-hit potential with Frenzy and Whirlwind, particularly if you dual-wield.  And what crit-monkey wouldn’t dual-wield?

Retribution: Has a 15% chance to become active for a short time when you are hit.  Using this skill deactivates it again.  Deals 286% weapon damage to all enemies in melee, and heals you by 5% of your maximum Life for each enemy you hit.

Retribution turns Revenge into an explosion of death, punishing your enemies very severely for daring to strike you in melee.  While it’s not as fantastic in the aftermath as the two earlier runes, for those who just need to hit really hard this rune is a glorious addition to Revenge, pumping its damage up from severe to absurd.

Grudge: Has a 15% chance to become active for a short time when you are hit.  Using this skill deactivates it again.  Deals 220% weapon damage to all enemies in melee and knocks them back 24 yards, and heals you by 5% of your maximum Life for each enemy you hit.

If you find yourself using Revenge in a dogpile and like escaping said dogpile better than exploding it, then you would rather hold a Grudge and come back after a moment.  Grudge serves this preference very well, giving you a good chance to delay things- whether so you can pick off individual enemies, so your allies can give you a breather, or just for the fun of sending everything flying.

Provocation: Has a 30% chance to become active for a short time when you are hit.  Using this skill deactivates it again.  Deals 220% weapon damage to all enemies in melee, and heals you by 5% of your maximum Life for each enemy you hit.

If you’d rather make Revenge more reliable so you can just apply it over and over again- letting you explode all over anything that dares clinch with you- then you’re looking for the Provocation rune.  With any other rune, Revenge is best used as a desperation move, since you have no guarantee of getting it back at any given time.  Provocation improves it to a near certainty that you’ll have Revenge when you really need it, even if you just used it a couple seconds ago.  It’s really a choice between stability (and frequency) or raw power (and side effects) that is hugely a matter of playstyle, rather than raw numbers.