I liked this one just a touch more than season 1.

Liked:
1) More humor.
2) The team relationship.
3) The music was perfect.
4) The cases and watching how they solved them.
5) Taking us back to a time period before some of the cases to see exactly how they planned to execute their jobs.
6) The acting of the main cast was excellent, with the addition of Shin Jae Ha as On Ha Joon - he was adorable, and sneaky, and creepy.

Difficulties for me:
1) It was so easy for the bad guy to figure out what the Taxi Driver and his team were doing.
2) SO many bad guys. The last scene in the prison, every person there was a bad guy!?!?!
3) To much violence for my liking. I would have preferred that they focused more on the cases and less on the violence.
4) They are easing dangerously close to a romance between the ML and FL. Romance has no place here.

So, if you are an action fan, give this show a try. I don't think you'll be disappointed.