Overall - I give it a 5 out of 5 stars just for my sheer love of the series but in the case of breaking down the different areas it falls to 9/10. My son has gotten me into anime after a long absence. I grew up on Voltron and Speed Racer when there was only four available channels to watch TV if that is any context. This particular show or series was a lot of fun. it had highs and lows and added enough intrigue to keep you going from episode to episode. I know I will watch this series again. I should actually remove some more from the story ranking since it didn't come out with another season. There was more than enough material to carry them through a second season without getting tired or deriviative.
Story - I will say that you have to let this one bake. I have seen it in other reviews and I agree that the story does not start humming untol the 5th or 6th episode. I also like the message it conveys throughout the series of friendship, togetherness, loyalty and, of course, love. Point deducted for the slow start.
Animation - Let me just say the 'regular' animation of all the characters was great. It definitely helped draw out their personalities. The issue I have with it is the emotional caricatures used when angry sad or blue. Understood why it is used but the regular animation was so good, i grew annoyed when they would move to the bubble stuff. Shout out to the animation when a tender or 'love' moment showed up. I though that was a neat touch. Still doesn't make up for the overuse of the secondary animations in my opinion.
Sound: All sounds songs and bakground music was great. Everytime I heard the opening music or the soft guitar chord int he background it made me get that slight smile like Kei when he is thinking of Hikari.
Characters - I thought hte character development was great after the first 5 episodes. I deducted a point because it would have been nice to see how some of the relationsips develop and if other characters do find a love interest.
Great, Great, Great series. Recommend it for everyone.