I suppose I can't use Joker as a favorite =P
(Note: This list does not reflect canon-lover status.)
There are quite a few characters I enjoyed.
I can see the merits in Ann, watching her constantly step forward even when she didn't know how, or where to go, but she did anyway; Results be damned.
Tae was a very fun character, what with her drugs and the lot
Futaba's personality in a whole kills me. The super h.acker mode to straning anti-social that she had was a fun blend.
I even loved to hate the characters you were suppose to hate. Lala also needed his own Confidant.
There were a few character that rubbed me wrong though, for a few reasons.
The first one is Mishima (Sorry Admin) He had a lot of potential, but it was mostly wasted on a Beta Male who was more obsessed with the phansite then a fish is with water. It left a lot of dry spots that kinda annoyed me where there could have been fantastic growth.
Hifumi was another character that missed their mark. She was a fantastic character with a lot of potential, but the fact she got cut tells me I can't judge it too harshly
Haru is a non-fleshed out character who is so much of a cliche "The world was handed to me and I hate it" stereotype that it really bothered me. Again, Story cuts, so I can't really be super critical
Yusuke - No, I will not get over the blackmail for nude painting ordeal. That's wrong on so many freaking levels, I don't care how "Corrupted by Madarame" he claims. He still have full function of his morality.
Morgana - Go to sleep... Kidding aside, Morgana was a wasted chance. He was more annoying then helpful, and his mopey "I NEED A REASON TO LIVE" stint felt way too forced, and was more or less a MacGuffin for Haru's intro.