Being a MASSIVE fan of the Hellblazer comics, I was dead excited to see that they were finally going to bring an accurate version of John Constantine to life. No offense to Keanu Reeves, who did a badass job, but Matt Ryan has done a brilliant job of capturing this character for who he really is.
To anyone comparing this to supernatural, PLEASE don't. Give me a break. Supernatural was INSPIRED by the Hellblazer comics (it's in the Supernatural Wiki). i.e., Constantine came first. Saying "we don't need another Supernatural" couldn't be more wrong. Supernatural has lost the plot, and is no where near as good as it was before. This brings an entirely new, fresh viewing of demons and angels and possessions. So far I absolutely love it and I really hope they stick true to the comics. I hope they won't rule out the chain-smoking just to calm viewers down. On a network that shows the Hannibal series, I sincerely doubt that chain-smoking is the thing to worry about when it comes to bad habits.
I loved the actual comic art they showed at the end of the first episode too. I can't wait to see where this series is going and I REALLY hope it continues. This series has what Supernatural has lost; a dark, gritty ambiance that makes the hairs on the back of your neck stand up. Definitely worth a watch, especially if you're a DC fan.