Coming in mid season, I'm not sure my reactions to characters are what they should be. I know I like Carter. This is a combination of my general love of cop characters and the fact that, in another show, she would be the main character. My first thought on her was that she knows she's the Commissioner Gordon in this situation. I like that her curiosity is leading her along despite herself.
Next I like Finch, I think that was what his name was. (I'd look it up but if I do that I'll never get a reaction written.) The Man Behind the Curtain. I'd expected more of a evil mastermind, and was pleasantly surprised at what I got. I find it amusing that he is the more expressive of the two male leads; his type generally isn't. By that I mean he's the brains of the operation, and they tend to be the colder, less emotive types. I also like that this (apparently) new kid is his nephew, extended family isn't used a lot in television and I like the complication it can bring.
I liked the guest characters. They had a feeling of reality to them. The lawyer was fun, I liked that she went to a dating website and that she fought with her shoes. The little details could get annoying, if they were only used to make characters quirky, but considering they can follow everything about a person's life, the show needs to have little quirks. I was a little relieved when they asked Carter for the lawyers sealed juvie record; then later I saw them getting arrest reports and I realized that was probably just a test for her.
Finally, I get to Reese. I honestly found him a bit sanctimonious. He appears to have some top secret training so he knows how this covert stuff works, and then this seems to make him take the high ground in arguments with any one who is not Finch. As the leg man and muscle of this operation I expected him to be a bit more volatile, but he seems to have the most even temperament I've ever seen. Same tone to describe almost getting run over by a garbage truck as to report findings on the person he's tailing. I will have to see if he grows on me.
All in all, I'm not sold yet, but I'll be watching next week.