I just loved it... I didn't have much expectations at first but the drama turned out to be very nice.
The romance is great and not so great. The childhood romance is warm and sweet. Once they get together, it's warm, sweet, funny, i smiled a lot. They understand each other, they talk and say what needs to be said (well note at first but later) it's very refreshing! The not so great is in the in between, there aren't really any sparks , not enough "impossible love moments" or not enough great "falling in love moments" but it works anyway.
The 2nd ML is great, the friendship between him and the FL is great, event if it's turns into a love triangle, they are absolutely great together.
The ending is perfect.