Just to clarify, I don't own a PS3 or 360, I only played a portion, and I hate Valve, but...

I played a little bit at a friend's house. The concept is just amazing, I'm not even sure how they came up with such an amazing creative idea, it just works so well and they made FPS cool, it's just so clever how they manage to use the portals and make you think outside the box.

However, they game wouldn't be as half as good if it wasn't for GLADOS. OMG she rules!!

She is so fun, and her voice is so deep but cold and cool and great, and her jokes and her ironies.. one of the most deep and amazing characters of all time, and I didn't even know her well.

I didn't get so deep, played about an hour.... but wow.... just wow....

Yeah well it goes back to 2007 with the first Portal.

And by the way, it's not actually Valve who came up with the concept.