Levi is the leader of the Survey Corps' Scouts, he gives brutal but true advices to teammates. He is tremendously fast and sharp in his skills. He's not afraid to get his hands dirty for the greater goods and more importantly he is a tea lover so am i ;)

Mikasa's best quality is her skill as a warrior. She was a credit to the Scouts, with her talents only being overshadowed by Levi's. This was due to her Ackerman lineage, as it afforded her significant bursts of energy in a short amount of time and she never loose faith in Eren.

Eren is a young man who is loyal to his people and sees no other way of securing their future than becoming death. The fact that he was willing to sacrifice his own life for the freedom of his peers is admirable, regardless of the means used to reach those ends.

L is simply a Brilliant, passionate, and confident person, only doubting himself once. All L wanted was to be involved in the solving of the case, which could mean saving lives. While the others wanted to be controllers of Kira,L wanted to be L.