SaiKano is a sad, sad series. And yet somehow uplifting by the end. The message of the series really sticks with you afterwards- it's that moving.
I love the characters the most- they're all so admirable in their own ways, and they each make their own sacrifices for the sake of someone special to them. That's what it's about; loving and trying to receive love, getting hurt in a confusing and quickly changing world but still struggling to go on despite these difficulties. I'll never forget a moment near the end that made me realize that the series started off in a vastly different world. It really brings home the irreversible effects of war, and the changes that the main characters have experienced.
This series is a good mix of pathos and cute moments (mostly courtesy of Chise) not to be missed. I haven't read the manga, but as a series alone, it is quite excellent.