The most important thing to understand about this show, and something I think wasn't understood by some people going in, is that this isn't anything deeply philosophical like Ghost in the Shell or something. It's not attempting to make any sort of grand sweeping statements about reality, society, or anything like that. That's not the angle they're going for here. At the end of the day, Plastic Memories is a love story. The early episodes focus heavily on their job, and thus their impact on society, but that serves mostly as a framework to give the rest of the show greater impact. And viewed from that perspective, it's fantastic.
The protagonist is honestly very refreshing. He's strong, but in a normal, human way. It's nice to have a main character who's completely aware. He understands what's going on around him, and deals with it like an adult.
I found Plastic Memories to be one of the more earnest, heart-felt romances I've seen in anime. It's honestly quite startling how some scenes seem to overflow with genuine pure love. The character development in the two leads is significant, lending credibility to their relationship. Their bond actually develops and grows, and they change as people because of it.
So sit down, grab some tissues, and go nuts. If you're looking for hard sci-fi or large-scale societal intrigue, this isn't that. If you like touching love stories, you'll like this.
