Support Class skill tree is bipolar: it can be built as a medic specialist (left side) or as an Overwatch specialist (right side).
Sprinter is preferred for most cases: Sprinter offers extreme utility especially if interaction is time critical whereas the penalties to reactive fire combined with the Support's inferior weaponry makes Covering Fire's additional chances for reaction fire of mediocre value.
- Sprinter allows 3 additional movement tiles.
- Sprinter synergies well with the use of Arc Throwers and Medikits;
- Sprinter is effective for strong positioning, flanking maneuvers, and supporting squad members. It is an essential promotion for objective(s) reliant on rapid movement:
- Sprinter stacks with movement bonus from Skeleton Suit and Ghost Armor, providing unmatched mobility.
- Covering Fire allows reaction shots to trigger on enemy attacks.
- Covering Fire provides "bonus" reaction fire opportunity in a situation where the player is certain that they need to suppress an enemy, rather than attempting to deliberately set up a situation where reaction fire can occur.
- Covering Fire synergies well with Rifle Suppression and Sentinel; it allows reactive fire against a suppressed target who fires and increasing the likelihood of two reactive shots per Overwatch exposed/flanked targets in an engagement.
- Covering Fire still incurs the reaction fire Aim penalty present with Rifle Suppression or Overwatch.
- Covering Fire frequently wastes shots and expends ammo at enemies in cover as Overwatch triggers cannot be controlled; it is generally safer to fall back and entering Overwatch as it is more likely to force an enemy to move up and be fired upon reactively while they are exposed and before they can fire.
- Covering Fire is improved in XCOM: Enemy Within by allowing Supports on Overwatch to shoot their targets before they attack. This includes the single-target Overwatch granted against the target of Rifle Suppression. Thus, this allows Rifle Suppression to reduce the enemy's Aim, and if it still decides to shoot, it will trigger the Support's reaction fire, and if this kills the target, this prevents the enemy's shot.
- Covering Fire should not replace "normal attack"; "preemptive tactics" are always superior to "reactive response".
Field Medic is preferred for most cases: given the strength of Squadsight Snipers at ending standoffs quickly, the tendency of Aliens and EXALT operatives to use grenades, rockets, psionic attacks and/or poison in the mid game, and the lethality of psionics late game, the niche for Smoke and Mirrors is quite small.
- Field Medic allows Medikits to be used three times per mission.
- Field Medic is one of the best overall upgrades for the Support class: three uses of the Medikit allows a liberal healing to keep the squad topped off between firefights, or three stabilizations, which can avert disaster if soldiers fall. It synergizes very well with a squad containing front-line troopers with the Secondary Heart gene mod, as it guarantees that these soldiers can be lose all their HP once per mission and without taking any permanent penalties whatsoever.
- Field Medic's effectiveness is greatly increased through its synergy with the Sprinter and Savior abilities and the completion of the Medikit Foundry upgrade.
- Smoke and Mirrors allows Smoke Grenade to be used three times per mission.
- Smoke and Mirrors suits a "movement minimalism" grand strategy, where the squad maintains a carefully placed cohesive formation while engaging long range standoffs against one group of foes at a time.
Rifle Suppression is preferred for most cases: Revive is a reactive skill that gets critically wounded soldiers back into the fight, while Rifle Suppression is a proactive skill that prevents allies from being critically wounded.
- Revive Allows Medikits to revive critically wounded soldiers at 33% of max health, instead of just stabilizing them.
- Revive has strong synergy with the Officer Training Don't Die On Me, or the Secondary Heart Gene Mod in XCOM: Enemy Within, due to the increased odds of soldiers falling critically wounded instead of being killed. With Secondary Heart, it virtually guarantees that those troopers can lose all their HP once per mission, yet continue fighting with no detriment to performance, thus making the player's squad very resilient to mistakes especially in Iron Man mode.
- Revive is a potential lifesaver but is a skill that is never used on a good mission; on a bad mission, it can salvage a potential squad wipe and hopefully open a shot at victory.
- Rifle Suppression fires a barrage that pins down a target, granting reactive fire against it and imposing a -30 Aim penalty.
- Rifle Suppression is a frequently useful skill that reduces the effectiveness of a foe's weapon fire against squad members with moderate effectiveness.
- Rifle Suppression is great for neutering Sectopods or Mechtoids, who can fire twice per turn; using two Rifle Suppression effects, should cause any shots against targets in cover to always miss.
- Rifle Suppression, like Smoke Grenades, encourages enemies to choose alternative attacks such as grenades, rockets or psionics; none of which are affected by the suppressive Aim penalty, nor trigger the ability's reaction fire. Careful note should be taken of which enemies are suitable for suppression and which types should simply be killed.
- Rifle Suppression's role can arguably be better fulfilled by Heavy Class soldiers they have a number of abilities that synergize well with Suppression.
Dense Smoke is preferred for most cases: Dense Smoke enhances the core functionality of Smoke Grenades where as Combat Drugs offers some moderate additional utility.
- Dense Smoke increasing Smoke Grenade's area of effect to 4 tile radius and Defense bonus to 40.
- Dense Smoke's total bonus of 80 Defense on allies in full cover is almost impenetrable (even on Impossible difficulty).
- Dense Smoke's increased area of effect aids in squad positioning and allows squad members to minimize the effects of AoE damage.
- Dense Smoke's increased defensive bonus is more likely to cause foes to re-position, use a grenade, or use abilities that aren't reliant on Aim; triggering the use of a grenade is an undesired outcome, as it both delivers unavoidable damage and destroys cover, leaving soldiers exposed to enemy fire. Thus, just as with Rifle Suppression, take this into account when deciding when to use it, and how to position your troops beforehand; Dense Smoke's increased area of effect aids in this regard.
- Combat Drugs grant Smoke Grenade a +20 Will and +10 critical chance for all units in the cloud.
- Combat Drugs makes Smoke Grenade a "Swiss army knife" of utility options; increased Criticals on two HEAT Ammo shots or an In The Zone spree can reshape the battle.
- Combat Drug's critical chance gain is marginal. The Will bonus tends to be ineffective protection against psionic encounters compared to conventional methods and rarely makes a significant difference, except with carefully planned circumstances (i.e. mass Mind Control attempts using multiple psionic XCOM soldiers to take control of multiple aliens in a single turn).
- Combat Drugs also grants a +20 Aim bonus not listed in the talent's description. This Aim bonus greatly assist relatively inaccurate Heavies at critical moments and supports lower ranking troops in landing shots to gain promotions.
- The Aim bonus has been removed in XCOM: Enemy Within, further reducing the ability's usefulness.
Savior is preferred in most cases: Savior grants a reliable increase to the core strength of the class, while Sentinel offers the potential for a double attack but suffers from the penalties of reactive fire.
- Savior doubles Medikits' restoration value to 8 health per use.
- Savior is a keystone skill for Field Medic, providing four heals for 8 hp (10 hp with the Foundry upgrade).
- Savior progressively increases in utility as the player researches advanced armor and equipment that allow troops to survive significant hits and benefit from the substantial healing that this ability provides.
- Savior allows a single well-prepared medic to significantly buffer a player's potential ability to recover from bad situations, turning many difficult missions into easy victories.
- Sentinel allows two reaction shots during Overwatch.
- Sentinel is the only way for a Support soldier to make two attacks per turn (thus roughly doubling a Support's damage output, the reaction fire Aim penalty notwithstanding), but is reliant on consistently getting two reaction fire chances per enemy turn. Pairing this ability with Covering Fire can maximize the opportunities for reaction shots. However take note that the other soldier classes all have more reliable and effective methods of making two or more attacks per turn, and arguably, a Support should be optimized toward maximizing their unique abilities instead.
- Sentinel also suffers from Supports' endgame weapon loadout (limited to the various tech-variants of Rifles) being the weakest of all the classes. Other squad members deal significantly more damage with their specialized weaponry, more reliable methods to make multiple shots per turn, and substantial critical hit bonuses.