I was hesitant to go into this because of the lowish rating (for mdl), but after reading lots of good reviews and comments I ended up watching it and I'm glad to say this is one of those dramas I think is underrated here on mdl. It's obviously not a new drama when you watch it, but if you enjoy the feel of older dramas, this encapsulates that feel and runs wild with it without becoming annoying!

Story (9.0):
Okay, there's no brilliant detective solving the worst crimes known to man or conniving businessmen taking over the world through genius cunning; there's nothing mind-bending and heart palpitating at all really. But the story takes a fun premise and carries that fun through to the end which I find a major accomplishment. Yes, it's not realistic and there's lots of stupidity that wouldn't hold up in a detective drama, but this isn't a detective drama! It's a rom-com folks!
And as someone who drops dramas right and left because I get annoyed or just don't want to watch anymore, I'm frankly surprised how quickly I flew through this one, especially since I've had a hard time getting through (romance) dramas from this same time period.
Personally, what I liked most through the show was the main character and seeing her change while remaining who she is; this was all given a backdrop of great supporting characters who became her friends and helped her become a better person. In the end, there was a marked difference from the selfish person we saw in the beginning, but she had also not changed who she was... It's hard to explain. I've never watched the movie this is based on, but I've heard the character had a more drastic change in that storyline. I think I would much prefer how the main character in this drama stays true to herself while also changing for the better. The PD for this drama said in an interview that he started that movie but never finished it and didn't know how it ended :D
One part of this story I was worried about was the second leads.
First, the female second lead, Yoo Kyung; honestly, there's not much to worry about. Yes, she tries to sink her claws into the man, but it doesn't bring about the annoying drama I hate so much. In fact, Yoo Kyung kind of shoots herself in the foot by being a bit duplicitous and not telling the whole truth before Chul Soo is firmly pointed in a different direction. That is, towards our heroine, Sang Shil (Jo Anna), who in contrast to Yoo Kyung, is very straightforward with who she is and what she feels, even if it doesn't give off the sweet persona Yoo Kyung has adopted.
In the case of the male second lead, Billy, it's a bit different, namely because he's already married to Anna. However, he somehow manages to shoot himself in the foot far more spectacularly than Yoo Kyung. In fact, he might have the greatest character arc in this whole drama as he makes the initial mistake and then tries to fix it by digging deeper and deeper holes and only realizing how far he's sunk by the time he's dug his own grave. Poor guy.
Anyway, I can't stand dramas that throw meaningless drama at the viewer to keep the story moving, and this did a good job of adding tension and drama without going overboard while throwing in dashes of comedy in all the right places. Finally, if you didn't know, this is a Hong sisters story! If you've liked any of their previous works, then you'll enjoy this one. Frankly, I have loved some of their works and promptly dropped others, so I was glad to see this stick to the straight and narrow.

Acting/Cast (9.0):
Han Ye Seul. Hate her or love her, I thought this role was perfect for her. Yeah, her voice got a bit overly screechy at times, most notable when she was arguing with the placid Yoo Kyung, but wow, it just worked. She made this role for me. As the rich Anna Jo, I thought she did a splendid job with her imperious and notorious look (I can FEEL that searing gaze in her wedding picture), but what really got me was how she played Na Sang Shil. I can't get over it and it's part of what really made this drama for me. And of course, you can't have Na Sang Shil without the reason for her antics: Jang Chul Soo!!!! (read that in her yelled voice as he turns away)
I have to admit, this might be the first drama Oh Ji Ho has starred in that I have completed. I'll be honest, whenever Na Sang Shil was on the screen, Jang Chul Soo kind of faded into the background as an accessory for me, but then when he had some emotional scenes, I was like, oh wait this guy can act!
There are some well known actors in the supporting cast and everyone regardless did a good job of portraying their characters. Due to the nature of this drama, there's a lot of the overacted style, but it usually seemed to fit.

Music (7.0):
Probably my least favorite part of the show, I'm still giving it a 7 because it was also a bit funky and usually fit the mood even if I can only remember 4 or 5 distinct pieces.

Rewatch Value (10.0):
I'm going out on a limb and proclaiming that I will without a doubt rewatch this drama. Personally, my favorite kind of shows to rewatch (which I do rarely), are ones that aren't too dramatic and are funny and romantic. This fits the bill perfectly.

Overall (9.0):
I'd say out of all the Hong sister dramas I've seen, this is probably #2 right behind Master's Sun. In my opinion, it's infinitely better than You're Beautiful which counts among the list of dramas I had to force myself (over many months) to eventually finish even if parts were fun.
I'll admit, going from a current Rom-com I was watching (Perfume) to this was a bit jarring in style, but they're both unique and I like both the old and the new. All in all, if you've ever liked an older drama or a Hong drama, then this should be just your cup of tea...
Or Makgeolli.