I am probably out of the choir here. I agree with most of the people about some choices, characters choices and plot choices sometimes are forced. However i think that if you are able to bypass some unnatural things you may be able to enjoy the show as i did. Overall the animation does its job in showing human emotions (which is, in my opinion, the core of this show). The music is very good.
The only really negative side is the writing. Even keeping the exact same plot with the exact same choices (sometimes too unrealistic even for me) i think they could have made a better job at justifying it. The focus was mostly on the emotions-tragedies side of the disaster.
[spoiler] Just a few examples: The leg injury of the girl (sorry i can't remember names) was shown all the time, but nobody ever asked anything, nor worried about it, including her mother. This was clearly leading to the end we saw. I don't criticize this by saying 'in those med kits or at the camp they could have found antibiotics', my critics is that they should and could have justified their incapability of finding antibiotics.
The same principle may apply to many other things.
The only things that i kind of hate is KITE, he's out of place. I could accept a survivalist wierdo knowing a lot of stuff and with some particular skills. But he literally saves a tetraplegic guy and comes back with a military amphibious vehicle. [/spoiler]