This build is great for split pushing, doing camps solo and team fighting. All the talents that go into Withering Fire will destroy groups of anything, but this is also it's weakness. You can't beat too many heroes 1v1. You will have to stay back and deal damage, which is pretty much the same for all of Sylvanas' builds.

Early on you will be weak, so use Withering Fire to harass the enemy until you can pick up Unstable Poison at level 7. After picking up Unstable Poison the enemy will have trouble pushing the lane.

Towards the mid-game when you have Wailing Arrow and Splinter Shot, you will be able to wipe out the enemy team in team fights. As soon as the enemy with the lowest HP is down, Wailing Arrows will be everywhere which will clean up the rest of the enemy team as long as you can kill one after the other.

Late game is where the fun really picks up. Fury of the Storm is usually a bad talent to get, but not on this build. You will one shot any size push. If you're behind and the enemy team is pushing into your base, you can wipe their team, especially if they are pushing with a large group of minions/mercenaries. The explosion from Unstable Poison can deal a huge amount of damage. Pushing into their base is pretty much the same, just wait for the minions to spawn and use Shadow Dagger to get Black Arrow on as many of them as you can.

You get 2 arrows from Splinter Shot, combined with Overflowing Quiver you will get 14 arrows from clearing creeps, 10 from killing enemies and another 10 from the 5 stacks of Withering Fire, plus whatever amount of times you can use Withering Fire during the fight.

In a large push from the enemy team, it is possible to get well over 60 arrows from instantly clearing their push and their team.