Pros:
Good AD
Good Speed
Good Ganks
Good Lifesteal

Cons:
Weak at beginnig
In a TF, if stun you, can die (you can't use your lifesteal)

You need to be faster...
Go at you buff blue and at 0:57 put a jack in the box,and when the cooldown back, put another and repeat until you have 4 jack in the box, the golem spawn and you can be 3 or 4 basic attacks and he die and you no lose life. (no use the smite, you go use to the red buff)

You have 2 options : Go to the wolves or go to the red of enemy team to counter jungle...
If you choose wolves, kill the wolves and go to wraits and put jack in the box and kill then. Go to the golems and put another jack in the box behind the great golem and kill then and the another. Go to red buff and put 2 or 3 jack in the box in the bush and use your E in the Lizzard to atract to the boxes. Gank mid or Bot, and after this gank top.

If you choose Counter jungle, go to the red buff of the enemy and put the max jack in the box you can in the bush. wait the jungle enemy and if he get down in the bush attack the max possible attacks and go to slow he if he run and get the first blood. If he not look you you can wait he attack to low HP the lizzard and you can only use smite and kill he. After this you can go and back to you jungle and repead the cycle previous.

Tips:
You can ask for your friends to defend the buff blue of enemy team.
If you counter jungle, and the Jungle enemy are on a lane far you can get the red buff and wait in the bush to kill he with news jack in the box. If he take long long to get you, you cna only leave and complete your cycle.