Simply love it! The story, the cast, the OST, everything.
I've watch the 20 episodes in a couple of days, I was so hooked to this serie that I couldn't stop for a day. 
The acting was really good, there was a great chemistry between the main couple, and I really liked that Chae Yeong Shin was a character with a strong personality (and to see her dancing :-D). I hadn't see Ji Chang Wook before this show, and I loved him doing different roles, overall as a shy and clumsy journalist.
I didn't rate a 10/10 because I think than even if the show is really great, there are some things I would have liked they'd have a better conclusive ending. For example, what did happen with Kim Moon Hoo brother? Did his wife do something about him lying all the time? I'd have liked to see a bit more of the main coupe life after everything is resolved... So, I know they're minor things, but it would have been wonderful to see them.
The OST was ok, I really liked the main song Eternal Love.
 Rewatch value: I don't usually rematch a show, except if I liked it very much (like Goblin and Strong woman Do Bong Soon), so there's a really high possibility I'll watch this show again in the future.
Overall: you should watch it... if you don't drop it before episode 3 or 4, after that it's impossible not to want to see what's going to happen.