The segmented nature of the series, where predominately a crime/issue was dealt within an episode, enabled the viewer to delve into a particular character/scenario without overarching distractions. I appreciated this episodic approach as it gradually built an rich and interesting universe that was gradually brought together at the end as all the actors came onto the stage. The overarching plot regarding the Laughing Man was very well done, and there was a very unconventional antagonist that I had not seen before.
Being a sci-fi/crime anime, character development was not its main focus. I found some characters likeable, and others quite frustrating and shallow. Funnily enough I related to the Tachikomas (robots) more than anything else. But I feel the development was solid enough for the anime to perform well. There are, as Matt pointed out, some big plot holes which can be difficult to ignore but nothing breaks the anime.
Very few anime contribute to our understanding of reality and push new borders like Ghost in the Shell has done, definitely a recommended watch for all.
