I came across this drama when I decided to I was going to watch all the dramas Seo Kang Joon has acted on. I loved his work on Cheese in the Trap and When the weather is fine. He played different roles in each and he did it amazingly well. Oh, his smile is to die for ;).
Unfortunately, I had to drop this drama right when I was getting towards the end. I didn't want to waste any more time watching it, so I just googled to know the ending. I mean, Nam Shin android does not feel any emotions, he is a robot. But why did it feel sad when the mum was paying more attention to Nam Shin human? This confused me and I found the story line lacking as I progressed.
All in all, this is just my opinion and it is watchable since I managed to watch 28 episodes of if. The main leads had great chemistry and I loved how Seo Kang Joon was able to play both roles so perfectly.