Firstly, I love Portal2. I've already finished the single player and co-op. Now, with that out of the way...
/rant begin
1. I'm really disappointed in Valve for the technical shortcomings of the console version. It's not even close to being a good looking game.
2. The load times are distracting and I find the switch between loading screens not nearly as fluid and artistic as it could've been done.
3. (Minor complaint) There is little variety in the pacing of the game and the environments. If decent dlc becomes available then this will make up for what was imo a very short game.
I was very surprised when this was touted as a 'big-budget' game. Looks like something a team of 40 people can do in a single year considering that the source engine was used.
/rant over
I would still recommend this game to anyone, and that's saying a lot.