Pros: Is great when split-laning, make sure to stay split-laning though.
If used right, then it has the highest chances of keeping Zagara alive.
Mediocre advantage in team fights.

Cons: Not best for team fights.
Takes away many of Zagara's advantages.

Other: The Nydus Worm storm talent is the reason for the heroic. Make sure to keep it hidden while near a lane. Zagara has high bullying potential, while this isn't the best build for a nuker, it gives Zagara ganking potential. Tumor Clutch is also a good tier 2 talent.

Pros: Ok for laning.
Is great when used against escaping heroes.

Cons: Makes Zagara a huge threat.
Makes Zagara Vulnerable.

Other: Make sure to not solo when using this build. Note, Zagara isn't an auto-attacker main and you should focus on using her abilities rather than her basic attack.

Tier 1: The reconstitution grants Zagara high sustainability if you are using her creep tumors properly. If not then I suggest choosing Corpse Feeders instead.

Tier 2: Not many people agree with me but the Medusa Blades keep Zagara's damage on multiple characters rather than just one. This damage is just like barely turning the lid on a jar. You caused the lid to be loosened allowing for it the just plop off. Coincidentally, this damage makes it easier to take down an enemy hero. If you do not like using this talent than I suggest getting envenom in its stead.

Tier 3: The Ventral Sacs talent helps to capture camps and allows for an extra tank for A.I. enemies to have to deal with. This includes Forts, Keeps, and the Core.

Tier 4-Heroic: The heroic depends on how the game is going. I suggest the Maw just in case considering the storm talent is not the best one should get, but if the enemy is going to constantly be pushed back, then I suggest the Nydus Worm for the fast travel.

Tier 5: The Grooved Spines talent is a great help, especially for those heroes who are always back line or running away. If used properly, than you might force a healer to run leaving their team vulnerable.

Tier 6:The Baneling Massacre is the main talent I choose, but not the only one. It helps when dealing damage to Minions, Mercenaries, Forts, Keeps, and the Core, but not necessarily so for enemy heroes. I choose Brood Expansion whenever I know I'm going to be getting into a lot of long-term team fights whereas the Hunter Killer ability provides more of a dps and tank rather than the banelings which are easily avoidable by the smart mind.

Tier 7-Storm: For this I choose the Fury of the Storm talent so as to easily clear lanes. If the game lasts for as long as it takes for you to get to level 20 than this is going to be best in both defensive and offensive strategies. If you don't like this talent, than I suggest going with the Storm talent that coincides with your heroic, however I highly prefer you to use this talent.