Just as awesome as the movie. Thrilling action scenes, badass fights, some comic relief scenes, a healthy dose of fanservice and some cute and romantic moments between Kirito and Asuna.
It's pretty hard to find (try raws if you know how to read Japanese), but Reki Kawahara wrote a very entertaining piece of media, and he should be proud of how great it turned out to be.
This movie/manga is canon by the way it takes place between the amazing Mother's Rosario and the glorious Alicization arc, read it you won't regret it.
The story between Kirito and Asuna you already know, but be prepared for
the beautiful and touching story between Eiji and Yuna, it'll swoon you I swear.
And lastly but not least, the WHOLE CAST is part of it, hard not to love it!
Story - 9/10
Character - 9/10
Art - 9/10
Enjoyment - 9/10
Overall - 9/10
P.S. I also recommend you reading the side stories Hopeful Chant and Chordial Chords, they take place before and after the movie respectively, and they're already translated, very easy to find.