Everybody and I mean everybody loves a great support player on their team.      They don't get much of the glory and unless their team makes some really bad decisions they are unlikely to ever have a shot at a Play of the Game moment, but support may be the most important role that exists in Overwatch. 

Four Great Choices.  Who Should I Play?

The beauty of playing support in Overwatch is that you really only have four options.   

Mercy

• Single target healer.
• Can boost one teammate's damage output, but only when she isn't healing.
• Able to "fly" to a teammate to escape danger or aid them. 
• Ultimate resurrects fallen teammates.   Can be game changing. 

Symmetra

• Doesn't heal at all, instead puts a small shield on a teammate. 
• Has an easy to avoid long-range attack and a strong close-range beam. 
• Can place defensive sentry turrets to slow and damage enemies. 
• Ultimate is a teleporter that allows fallen teammates to quickly re-enter the battle.  

Lúcio

• Primary healing is area of effect.  Just stay close to your teammates and they are healed automatically. 
• Healing can be swapped for a speed boost, but both can't be "UP" at the same time. 
• Can provide some damage through primary fire.
• Secondary fire is a push that is excellent for knocking enemies off ledges, down wells, etc. 
• Ultimate is an "overheal" that adds HP temporarily to every teammate within range.  

Zenyatta

• Uses orbs.
• Orb of Harmony heals a teammate.   Teammate must remain in LoS.  
• Orb of Dischord attaches to an enemy.  Enemy takes 50% more damage from all attacks. 
• Has no good escape mechanism. 
• Does quite a bit of damage if left unchecked. 
• Ultimate makes Zenyatta invulnerable and immune to crowd control.   Heals teammates for an immense amount. 

Support Power

Pure Healing

1. Mercy - Undisputed best single target healer and her ultimate is a full heal resurrection to any teammates that are dead. 
2. Lucio - Undisputed best area effect healer.  His ultimate counters many damage dealing ultimates.
3. Zenyatta - Orb of Harmony does effective single-target healing, but requires that target be in line of sight. 
4. Symmetra - Shields are a poor alternative to real heals. 

Non Healing Abilities. 

1. Lucio - Speed boost gets team to control points and payloads faster than the enemy.  Invaluable.   His alternative-fire "push" can save a teammate or kill an enemy.   Wall running can keep him out of harm's way as he contests a point in Overtime. 
2. Symmetra - A teleporter is invaluable on some maps and useless on others.   Sentry turrets can be a nuisance, but are easily dealt with by above average players. 
3. Zenyatta - Orb of Dischord is an excellent damage boost if you can get your team to focus fire. 
4. Mercy - Single player damage boost can be effective, but is only available when she isn't healing. 

Barrier To Entry

1. Lucio - One of the easiest Heroes to play adequately.  Stay close to your teammates, speed boost when appropriate and otherwise shoot the bad guys. 
2. Symmetra - Place your sentries.   Place your teleporter when applicable and don't die.   You spend a lot of time out of the action. 
3. Mercy - Average players keep a heal on a teammate and may occassionly damage boost someone.   Easy to play at this kind of level. 
4. Zenyatta - Very squishy with a lot of decisions to make.   His barrier to entry is the highest of any support.   An average Zenyatta is doing more thinking, shooting and moving than any other average support Hero. 

Skill Ceiling

1. Mercy - The hardest healer to play at a high skill level as she has to make split-second decisions that can have catastrophic effects.  Even using her ultimate is a decision not to be taken lightly.  Who is down?  How far is the spawn point? Will I lose more teammates as I try to resurrect the dead?   Her positioning is paramount to her success and new players simply don't have the experience to position themselves well.   
2. Zenyatta - Positioning is key if even to keep a healing orb running on a teammate to continues to run out of your line of sight.   Who should get the Orb of Dischord?  When should you pop your ultimate?  Is it safe to stay behind your team or would you be safer closer to the action?  Who does the other team have that can hard counter you?  Where are they?
3. Lucio - Great Lucios are a sight to behold, but they still have less to do and think about than either Zen or Mercy.   Your twitch abilities need to be superior to other supports, but your mistakes aren't punished as harshly. 
4. Symmetra - By far the easiest support to play, but also has the least to offer. 

Final Choice

1. Lucio [Guide] - He offers the most healing and the most auxilliary support to the team with the least amount of initial skill and map awareness of any of the support choices.    Don't assume to be great with him will be easy, but it is relatively easy to be good with him.
2. Mercy [Guide] - Tough to play really well, but she can provide support by using a minimal toolset.   As you learn to be more map aware you will find that you can move outside of your comfort zone more. 
3. Symmetra [Guide] - Incredibly easy to play at an average level.   You can't heal, but if your team has a healer and you are defending she is always a good choice. 
4. Zenyatta [Guide] - He's the weakest of the supports and also the hardest to play at even an average level.   He's damn fun though, but this isn't about that.  It's about being the best choice for a new player and he most definately is not that. 

Congrats Lucio!