First of all, let me say that Seo Kang Joon is AMAZING in this series. He pulls off both the roles with an amazing ability to separate the characters and give them each their own personalities. The entire cast was great in this, but I was really impressed with Kang Joon's acting. Doing one role well is difficult, to do two this well is indeed an accomplishment.

As for the story...the plot is interesting and keeps you wanting to watch. My favorite scenes were with the two lead characters because they played off each other so well and I really liked that the female lead (played by Gong Seung Yeon) was strong and impressive in her own right. She teaches the robot Nam Shin how to be more human and it's fun to watch him grow. I also really enjoyed the scenes between the robot Nam Shin and his right hand man, Ji Yeong Hoon (played by Lee Joon Hyuk). Their growing friendship was also a highlight of the show.

The only thing I have a bit of a gripe about is that the ending felt a bit rushed. Though it pulled all the pieces together and you didn't feel like it left you hanging really, but it was like it needed another 10 minutes to really finish the story properly. But other than that, this is a solid drama and well worth the time to watch. I recommend it.