The City Side of Town did this so much better, not to mention other episodes making fun of "city" people. Here the joke is amusing but one note, and used and leaned on throughout the episode. Much like Mr. Kim use of the word city. And obviously Cartman was just being manipulative.
There's some amusing parts to this episode, like with the realtors, but not really laugh out loud funny and it felt too safe. I also felt they could've done a better job focusing on or examining Eric and his mom's relationship. Especially since we came away with nothing new. We already know Cartman is a master manipulator and his mom always caves and caters to him. Maybe this is just a set up for a season character arc?
Overall this episode was forgettable, the writing lazy and, worst of all, it was boring.