Overall, I really enjoyed this drama and have watched it several times. It had a good combination of romance and friendship, and was also good at depicting realistic (or at least more realistic than your typical drama) struggles in achieving one's dreams.

The acting for me was pretty good, there were some moments where it was a little "drama-like" but for the most part it was very believable and enjoyable.

The chemistry between the leads was great and had me rooting for them all the way through. It was very satisfying when they got together and there were several episodes (the final ten) where you got to see them as a couple (which is good as a lot of dramas end when they get together and don't show you much afterwards).
I really liked the development between the two leads (although I must admit there was a bit of a jump - although not too bad - during the transition between conflict and the start of their friendship), particularly how they became friends before they became lovers. The story allowed them to get to know one another and see/help each other during some struggles before they officially became a couple.

*SPOILERS AHEAD* - skip to the end of review if you don't want to read

In terms of criticisms, some people have said that the first couples of episodes are a bit slow/boring - which I can understand, however, I would suggest to keeping watching past those episodes as it does get better as it goes.

Personally I was annoyed by the ex-girlfriend story-line. They used it multiples times during the second half of the drama and I honestly found it irritating. The first time was fine, but afterwards it was just annoying. In this case it was an ex-girlfriend who couldn't accept that the main lead had moved on and it was just too much and repetitive.

Something I didn't like was that in this drama there were only two kisses between the leads and both occurred in one episode (ep 26 or 27). There were several occasions where they could've added another and it would have been very natural and cute, but unfortunately that did not happen (not even in the last episode). This might not bother you, but it did bother me a little.

Another things was that the two leads had some conflicts in the final few episodes and then in the last episode they made up in the final ten minutes and all was well. It was a little sudden and the conflict was rather frustrating (refer back to ex-girlfriend comment) - particularly since their relationship was being developed really well in the last ten episodes.

*SPOILERS FINISHED*

Overall I really enjoyed it. While it had some flaws, I thought that this drama was one of the better dramas I have seen. It was refreshing and more realistic than most and the chemistry between the two leads were really good.
I love to come back to it and should you choose to watch it, I'd hope you can like it too.