Finished Shadow of the Colossus a few days ago. I have mixed feelings about this one. The core gameplay is solid enough, but the game's utter lack of back story didn't give me much motivation to press onward and it'd be nice if there was some indication in the game itself that eating fruit and killing white-tailed lizards is a smart thing to do. If the manual hadn't advised me to do this, I probably would have had a much harder time with it than I did. I'm also torn about the size and freedom offered in the world. On the one hand, I think it's great that you have the freedom to go anywhere right from the start, but on the other hand, I found myself wasting enormous amounts of time just riding around the map looking for lizards and fruit. By the end of it, I was pretty damn sick of riding the poorly controlling horse around, and I just wanted to kill some giant monsters and be done with it.
On the whole, I think Ico is probably the better of the two, but they're both worth experiencing, and I'm glad I finally got to play through them. Here's hoping The Last Guardian fixes all the issues I had with these and makes me want to crown it as my GOTY for 2012.