I must say this was very enjoyable read despite its short length.
Story: Simply outstanding story, as expected from KEY. An excellent story from start to finish, however I did find a few things confusing such as Tomoya's memory loss, like many of KEY's works, its a finely tuned story.
Art: I wouldn't say it is a masterpiece in artwork, but the drawing is well done nonetheless. A good mixture of fights, touching moments, and chibis here and there.
Character: A small cast of characters, but definitely one that I loved very much. However, from what I have seen in the Clannad anime, Tomoyo's personality has changed alot, for better or worse it depends on how much you liked her in Clannad. The cast is diverse and I enjoyed each's character's appearance and the impact they have when you read through each chapter, an element of becoming strong.
Enjoyment: Like I said, short, but awesome. It has become one of my favorite manga of all time and I hope that it will be made into an anime, as it could be very promising.
Overall: Despite not getting a perfect score, I absolutely loved this manga. I was pretty skeptical at first why Tomoyo would even have spin-off series for herself instead of continuing her arc in Clannad. But I see Tomoyo's character in a different light now, and become one of my favorite characters in this manga and in Clannad as well.