Pros

A very high chance to have a pentakill
Very High Survivablity depending on user
Able to dish out Large Amounts of DPS
Kiting will be easy
Great Healing advantages
Does not Mostly Depend on Team mates

Cons

Is mostly targeted by enemies
Not advised for cowards
Slow damager

Infuse will let you Deal Damage at Long range for easy Kiting ang for making Opponents angry :P
What Else? Drain Their magic resist and chase them away with this helluva skill. Can be useful for farming and killing minions.

This will let you get nearer to enemies with its bonus armor. This will also recover all your sustained damage from getting near with starcall. Very Useful
HEAL!!!! Yes, Heal.

The Provided Core items will give defense and mana regen for prolonged fights so you dont have to worry about losing mana (or health) at the same time dealing large amounts of DPS.

Rylai's will slow the enemies in order for you to chase them more and annoy them.
In addition to Rabadon's DC, DFG will Deal Very Much MORE DAMAGE unless if you want to sacrifice your defensive items though Then Replace Abyssal Scepter. Its all up to you what combinations to use.

Ghost Flash Ignite BLABLABLA
Anything can do! This is Soraka!

All in all the one goal is to Dish out Large amounts of DPS, Heal teammates and sustain yourselves AND be the key to winning. Good Luck Summoners and i wish you luck!