I loved the episode. Loved the passage of time and the difference in characters. Especially in Carl. The change in Lori and Rick's relationship is pretty interesting too.
I for one never complained about a lack of zombies. How boring would the show be if we knew they were going to be fighting swarms of zombies every week? It's better if we don't know where and when they are going to show up.
the executive producer was on Talking Dead tonight. He wrote the episode and said that the prison set was built before he wrote it and he walked through the set to decide how Rick would go about taking it.