They're incredible, but a little hard to get into at first. I played the first game on and off for a few weeks until I got to where the plot takes off. I then played for five hours straight, staying up way later than I should in an attempt to finish. I did, but I was so tired at work the next day. I didn't care, it was worth it.
The other two games are also kind of like that, only you're already invested in the game.