...you definitely shouldn't bother with this manhwa. In fact, you shouldn't read it even if you "have nothing against BL but still don't want the two male leads to end up together" ;)
There isn't anything particularly revolutionary or ground-breaking about the story -- but it's simple, charming, and sweet in a way most shoujo-esque romances and contemporary BL are not. The characters (especially Seung Hun, but Woo Sun as well) are very likeable, and they really bring a unique flavour to what would otherwise be a stereotyped high-school love polygon. Not to mention, Moon Sun and his girlfriend Hae Jin make the most excellent example of a beta-couple I've ever seen; providing comic relief where necessary but also giving out serious advice to their "less experienced" friends when the occasion called for it.
I also liked how Jong Yi's relationship with Yu Ri played out; it revealed a harsh, self-centred, but still somewhat kindly side of his personality that was well concealed behind his vacant, childlike façade and took me very much by surprise upon its revelation. It's obvious that many people (such as Trimutius, below)
were expecting them to end up together -- but I for one am happy that the manhwaga didn't take the easy way out by going that cliché route.
It's true that the ending was unnecessarily sappy and romantic, full of talk about "first-and-only love" and "love at first sight" -- neither of which I believe in -- but that didn't detract too much from the overall mood.
The art was very simple and plain -- and the backgrounds almost entirely consisted of painted-over photographs -- but that didn't matter much because this is a character-driven story and not an action-oriented or strongly atmospheric one.
All in all, I'd recommend C.O.Y. to anyone who enjoys softcore BL with some shoujo romance flavouring on the side.