So I finished Portal 2's single player over the weekend, and I still hold to my previous comments. Portal was such a better game all around. I felt they drug out the game-play maybe an hour and a half too long with the "story". The ending felt contrived and out of place considering the rest of the game. It was a good game, just not the great game some people were making it out to be.
I tried to get my wife into some of the split-screen co-op with me, but after a few puzzles she hit me with "Is this all it is? This is boring..." and "is she [GLaDOS] going to talk the whole time?"
This is from someone who doesn't play a lot of hardcore games, but sees me play plenty of games. She wasn't even that interested in the story or the game play. I'm sure I am in the minority still, but this game is far from Game-of-the-Year material, and I really hope that is evident by the time those lists roll around.