I watched the first 2 episodes of Constantine yesterday (finally), and at first, I honestly didn't really like the feel of the show. That was primarily because of the quialiy I was watching it in, and it reminded me of the quality of shows airing around 2005, and I wasn't really happy with that, considering how far TV graphics and special effects have progressed since then.
Nevertheless, when I found out that Constantine was based off of a DC comic, I thought that it would be nice to watch. After watching the second episode, however, I had a slightly better grasp on the show, though in some ways it reminded me of Supernatural, due to them finding paranormal cases across America, and then going to resolve each one at a time. Plus, the first season is about finding a demon.
I do realize that to truly judge the show, I need to watch more of the show before I can say anymore, but for those that don't find what I say to be true in anyway, the following is for you:

See the similarity?
Also, I loved this easter egg in the piolt for one of the most iconic DC mystic heroes (for anyone who knows it):