I've only see the pilot but it was a slick, fast-paced piece of work. They wasted no time getting into the story (stories) and to cover that amount of info in an hour without confusing or tiring the viewer was impressive.
The story centers around a gal who was special forces and is now part of a private sector (counter)espionage team. I won't get into any more details than to say she's hardcore.
I also have to say that I've always liked Melissa George, she can act and she does a believable job in action sequences too. She perfectly suited to this type of show, and the show works because of her.
The rest of the main cast, though largely unfamiliar to me (which means nothing), are clearly pros as well. They carved out their niches in the short time allotted to them and it's always a treat to have a strong supporting cast.
The show is definitely worth a watch.