Hope – Medic Crystarium

Character Hope
Role Medic
Hope has access to every Medic Ability, which combined with his high Magic stat makes him the best Medic in the game. He is one of only two Characters (along with Vanille) with access to Curaja, a vital Ability when dealing with powerful multi-target attacks from the game's tougher foes.
Compare Hope – Medic Crystarium to other Crystariums

Related

Hope

Eidolon Alexander (Chapter 11)
Base HP 170
Maximum HP 18,000
Base Strength 8
Maximum Strength 1,100
Base Magic 20
Maximum Magic 1,900
Starting Weapon Airwing
Primary Roles Ravager, Synergist, Medic
Accessory Crystal Synergist 3
Accessory Crystal Medic 8
Accessory Crystal Ravager 10
ATB Level Crystal Synergist 8
Chapter 1

Fang – Medic Crystarium

Character Fang
Role Medic
Fang has access to the same Medic Abilities as Lightning, but because it's a secondary Role, she's even less useful as a Medic. By the time you are likely to learn these Abilities, the lack of a Curasa spell means Fang will be terrible at healing. Her only real advantage over any other Medic is that she gets Raise (which Sazh and Snow do not), but you're more likely to use Renew or a Phoenix Down late in the game anyway.

Hope – Commando Crystarium

Character Hope
Role Commando
Hope's biggest disadvantage as a Commando is his low strength stat, but then, he gets Ruin right away so that shouldn't be a big issue. In fact, Commando can be very effective for Hope against enemies that are weak against Magic but resist most Elements. He lacks many auto Abilities, notably including Launch, making him a poor choice as your lone Commando, but then, you're not likely to use him in that Role.

Hope – Ravager Crystarium

Character Hope
Role Ravager
Hope is the best Ravager in the game, provided your target is not more vulnerable to Physical than Magic attacks. The only Abilities Hope lacks are the -strike Abilities, which is usually fine but will occasionally make him virtually useless. Hope also has the Last Resort special Ability, which will very rapidly build the chain bonus of a staggered target.

Hope – Saboteur Crystarium

Character Hope
Role Saboteur
Like Sazh, Hope is one of two Characters that can inflict every Status Ailment in the game. However, Hope exclusively gets multi-target versions of these debuffs (as well as the standard Dispel). This makes Hope an effective Saboteur against groups, but since his Abilities cost three times as many ATB segments, he's a liability when you're only looking to debuff a single target (which is usually the case). He can't even use two debuffs in a round without the Nue.

Hope – Sentinel Crystarium

Character Hope
Role Sentinel
Despite having the lowest HP in the game, Hope makes for a fairly interesting Sentinel. Like Lightning, he doesn't get Challenge and favors Elude over Mediguard and Steelguard, but Hope also gets the counterattack Abilities, Entrench and Vendetta. He's fun to play around with, but not much use against truly powerful enemies.

Hope – Synergist Crystarium

Character Hope
Role Synergist
Hope, like Sazh, eventually gets almost every basic Synergist Ability (though he gains Veil over Sazh's Vigilance). Until Chapter 10, however, Hope is primarily a defensive Synergist, with Abilities like Protect, Shell, and Bar-spells. Which of the two is more useful depends largely on how hard the enemy in question hits.

Lightning – Medic Crystarium

Character Lightning
Role Medic
For most of the game, Lightning is an effective Medic, if not quite on par with Vanille and Hope. As the game wears on, she becomes better as a secondary Medic, and by the time you're mastering multiple Crystarium Roles, she's all but worthless. This is entirely due to her lack of access to the Curasa Ability (to say nothing of Curaja). Cure just won't cut it once your party's HP is in the five-digit range, limiting Lightning's job as a Medic to casting Esuna and perhaps Raise.

Sazh – Medic Crystarium

Character Sazh
Role Medic
Sazh never gets access to Raise, but don't let that fool you into thinking he's a bad Medic. He doesn't get Curaja (that's reserved for Vanille and Hope), but he does get Curasa, making him an effective healer through endgame fights. That said, he won't get Curasa until Crystarium stage 9, and it's quite expensive.

Snow – Medic Crystarium

Character Snow
Role Medic
Snow has the same strengths and weaknesses as a Medic as Sazh—no Raise (which is no big deal) and eventual access to Curasa (which is very important when dealing with the most dangerous enemies). If you're actually going to use the Salvation paradigm (MED/MED/MED), make sure you're Characters who can at least cast Curasa.

Vanille – Medic Crystarium

Character Vanille
Role Medic
Vanille and Hope are the only Characters with access to every Medic Ability, and while Hope's magic stat is naturally higher, Vanille is plenty effective as a Medic as well. She and Hope are the only Characters who can use the amazing Curaja Ability, a vital healing spell in the endgame.

Medic

Bonus Type Augmented Healing

Medic

Abbreviation MED
Role Bonus Augmented Healing
Base Bonus (Self) Healing Bonus: +10%
Role Level I Bonus (Self) Healing Bonus: +20%
Role Level II Bonus (Self) Healing Bonus: +30%
Base Bonus (Allies) Healing Bonus: +5%
Role Level II Bonus (Allies) Healing Bonus: +8%
Role Accessory Healer's Emerald (Grants Healing Bonus: +5% to self)