Shingeki no Kyojin is a master piece among master pieces. Each chapter keeps making you come back for more. After you start reading this you wont be able to stop. I can't find anything that's good as this. The plot development, art, characters they're all written so amazingly it sometimes scares me of how good this is. When you read the manga it never gets boring, there is always something that happens to keep you on your toes to keep wanting to read more. The character development that all of them went through was the best I've seen. Every time each arcs comes by something new happens that you never expected weather it's betrayals, the past we never knew, or the reason behind the characters decisions. It goes through step by step explaining why the characters did what they did and why, it explains in such good detail that makes it amazing. The art of the fights, titans, characters are the best I've seen, it's amazing how the author came up with such a good story and made the art for the good story he wrote.
Overall: this manga is 100% worth reading and you should take the time outa your day to read it all the way through the end.