For those who have seen it, here comes two most common questions:
1) Haruka or Hayase ? Why ?
2) Takayuki - BAKA (idiot) or great guy ? Why ?

I have seen it and i bought the first 2 DVDs got the 3rd DVD on pre ordered. known as (Rumbling Hearts)

I would choose Haruka, because omg such CUTENESS!!!! plus she's a very nice and very thoughtful girl. She tries very hard and makes sad choices.

Takayuki, hmmm I wouldn't blame him...because 3 years is a looooooong time I would understand if he has another girlfriend now...but if it was me..I'd have my heart stick to Haruka until she wakes up, even if she never wakes up I'd sitll love her, I'd wait until the end even if I have to(bad thing to say but yeah..but it's the truth) ..thats the person I am.

Haruka - Haruka is a cute girl that is very shy. She would probably do anything for Takayuki is she wanted to.
Hayase - Hayase liked Takayuki, but for Haruka, she introducted those two. After the accident, Hayase's feeling for Takayuki feelings starts to come back after seeing how much pain Takayuki has when Haruka was in the hospital.
Takayuki - He's just a regular guy that wanted to have a normal live, he cared about both girls. The day of the accident was also Hayase's birthday. As a normal guy, you would also want to buy presents for a person's birthday. He just didn't think anything would have happened to Haruka if he was 10 minutes late.

The anime is sad and very dramatic in a lot of events and decisions.

Takayuki didn't forget about Haruka, he just didn't love her as much after Hayase starts to make him have feelings for her.
Also, Haruka's parents made it very clear that they didn't want Takayuki to go near Haruka anymore.

I believe the most to blame in the anime is Haruka's parents not knowing Takayuki's determination he has on Haruka and didn't let him have any feelings toward her for 3 whole years.

Well, the parents don't want to see him like that. So the decision had to be made even if it was a sad one.

Actually, it's not the parent don't want to see Takayuki sad...

The problem was because Takayuki's actions...
In one of the episode, it showed that Takayuki wants to bring Haruka to an Art festival, so he tried to bring her out of the hospital.

The parents and doctors stopped him, and that's when the parents tell Takayuki to stop seeing their daughter.

The parents wants to protect their daughter, not to see Takayuki sad, the parents doesn't really care about how Takayuki feels.