Yes it was exceptionally corny & heavy handed. Drippy, gooey and overly sentimental but isn't that also what Titanic was and it certainly didn't hurt Titanic. I think it actually helped it same as it does with this series.
I am a cynical, born NYer and this series made my eyes watery (Actually it made me cry several times). Kazuya Kamenashi was wonderful in the lead delivering a moving performance of torn stoic youth having difficulty with a hard life & his inner emotions and was all doey eyed swoonable handsomeness. Haruka Ayase was beautiful & equally moving in a fragile delicate way as his budding gf. Their romance was, even with all the emotional corn syrup, touching and warm hearted. Their courtship's development was very sweet and wonderfully detailed in small charming ways that would elude most American TV programmers out to find the new Dawsons Creek/Gossip Girl oversexualized fakery.
Koki Tanaka, Kamenashi's co-member from the popular J pop group Kat-tun, was way too over the top hammy in his role but even he gets in an effective scene in the drama. The supporting cast was mostly good and the show itself is well directed by Hitoshi Iwamoto offering up a diverse pictorial of its characters & locations. The series main theme song "Cool Whispers" by Ike Yoshihiro is pretty darn catchy too and like Celine Dion did with Titanic, meshes perfectly with the series.
I encourage those who enjoy well done romantic goo to find & watch this emotionally fervid series. I dare you not to be brought to tears at least once and luxuriate in it's sweet teenage romantic angst of the heart. Poor boy, rich girl, interfering parents, handicapped sibling, romantic theme song, conniving exes...get the Kleenex ready.
Then you can also watch Kamenashi & Tanaka on their "Kat-tun Cartoon" J variety series if you wish to see them again in a different context.