Definitely worth watching.
It's a peculiar concept as it is three mini stories that revolve around a couple who were destined to be together but their distance keeps that from happening. It is interesting to see how their young love blooms in the first mini story and watch how their relationship progresses and evidentally deteriorates as it doesn't seem to be a topic much covered in anime. Primarily, I didn't think much of the actual storyline, since it was split into three parts it was difficult to really feel any sense of a secure plot, however they do make you care deeply for the characters, especially in the second segment.
I would recommened this not for the story, but primarily for the animation. Never before have I been so unbelievably blown away by how beautifully stunning japanese animation can be. This in my opinion is one of the (if not the) best looking shows out there at the moment. Simply and utterly breathtaking, it's worth watching just for the amazing visuals.