As US shows go, it's not too bad. I like it a lot better than "Smallville", which I note was produced by the same people.
I'm just halfway through the series at the moment, and just came to a major plot twist that I *really* didn't expect - kudos to them for being unpredictable.
There are a few small "throw-aways" to watch out for; references to the meteor showers in "Smallville", for example, or tilted introductory shots of the "criminal's lair" that hark back to the 1960s high-camp "Batman". So far so good. It's a shame they canned this and not "Smallville". With Smallville's budget and a rewrite to play down the "meta-human" conceit this could have become unmissable.