I'm not a fan of cop shows ("Castle" doesn't count), but I thought I'd watch this since it was set in my favorite city in the whole wide world. Visually, I liked it a lot; there were some nice shots of the city, and if the El was overrepresented, I trust those were just establishing shots. It was jarring to see everything so green and pretty, but also kind of nice, even if I did spend as much time trying to identify the places they were driving through as I did paying attention to the story, LOL.
The characters were interesting enough, as much as you can get out of a pilot...there was the obligatory Cubs vs. Sox argument, although I was amused at how the usually-deferential newbie got enough of a voice to talk back when it came to defending his team. :) The voice-over thing as an intro to the characters was a little jarring, but it turned out to be really effective with Antonio getting cut off in midsentence. Don't really approve of the young female cop sleeping with her partner (and the older cop assuming she was), but the superintendent was awesome enough to make up for it.
As for the overarching storyline....this is a good explanation of why I'm ambivalent about it. "Chicago politics" is shorthand for the way many major cities in the U.S. used to run, and the way Chicago still is (although the scandals are usually more along the lines of pay-to-play than murder-for-hire). The corrupt alderman in the episode had a great line about how the "works" in "the city that works" means something a little darker than you might think. At the same time, it frustrates me because when you give a problem the label of Chicago politics, you can shrug your shoulders and give up because there's no way to fix it, and then you can start tagging everyone who comes from Chicago/Illinois with that same corrupt brush. So I'm hopeful that because this show is about people from within the city, or at least the police force, working to change things, that you can fight City Hall. Guess we'll have to wait and see.