Trinity / Trinity Prime is the most versatile healer/support Warframe, as she can reduce incoming damage and restore Health/Energy/Shields of nearby allies, companions, Eidolon Lures, hacked drones etc. Her abilities make her very useful when hunting the Eidolon bosses as she is able to reduce incoming damage and heal not only the team itself but also companions and the Eidolon Lures. Furthermore she can provide Overshields and restore energy to nearby allies, which allows for  a faster fight.

The main disadvantage of Trinity is that her blueprints are a lot harder to farm than most other Warframes; futhermore the relics that drop blueprints for Trinity Prime are currently vaulted.

Trinity's blueprints drops from Ambulas @ Hades on Pluto. Trinity is one of the harder and more time consuming Warframes to farm as you must first farm 20 Animo Navigation Beacons in order to gain access to the Ambulas mission; these nav beacons are obtained by destroying and hacking "Ambulas" robots deployed from dropships on outdoor tile sets on Pluto. I actually got Trinity Prime long before I got the standard Trinity...

The relics that drops blueprints for Trinity Prime are currently removed from the drop tables and have been moved to the "Prime Vault". They will likely be unvaulted again at a later date - pay attention to news on the official Warframe site for information of which warframes gets unvaulted next time. You can however still acquire those blueprints by trading with other players (for Platinum) who already possess those blueprints.

1: The Well of Life ability incapacitates the target an temporarily grant the target 10x more health for 12 seconds. During this time all damage done to the target will heal nearby allies (up to 400 health points). However, many bosses are immune to crowd-control abilities and can not be incapacitated by this ability.

Hint: The Well of Life ability can also be used to lock down a Synthesis Target for scanning.

Mods:

• The lifesteal and maximum health scales with Ability Strength.
• Duration scales with Ability Duration.
• Cast range scales with Ability Range.
• Augment: Pool of Life cause enemies marked with Well of Life to drop Health Orbs when killed and also have a chance of dropping an Energy Orb.

2: Energy Vampire marks a target with a bright blue light. The marked target will emit pulses that restores energy to all allies within range (25m). The target will be staggered and take True Damage (ignoring shields) for each pulse; however, some enemies, e.g. many bosses and some heavy enemies, are immune to stagger.

Mods:

• Damage and energy restore scales with Ability Strength.
• Pulse duration scales with Ability Duration.
• Cast range and pulse radius scales with Ability Range.
• Augment: Vampire Leech cause excess energy to be converted into Shields and even boost into Overshields.

3: Link channels all damage taken to a nearby enemy - this also includes Status effects.

Notice: Avoid using mods that reduce your Ability Range as this can cause this ability to fail linking to nearby enemies!

Mods:

• Higher Ability Range will make it more likely that Link is able to connect to a nearby enemy.
• Duration scales with Ability Duration.
• Augment: Abating Link reduces the armor of linked enemies.