I might go for the flame award, but AC somehow wasn't my cup of tea, although I actually liked The Spirits Within.
Thinking about it, the graphical style in AC was too cold for my taste.
I somehow got the impression that everything happens in a big fridge (I know that this sounds strange). Even worse, the development of the story is lacking, too, which left me with the impression that AC is a movie that was composed of individual cutscenes.
I am by no means a film critic and there might be people around that can explain the reasons a lot better, but all in all, AC just seemed like a big fanservice act to me. FF7 actually had some diverse characters with individual traits and interesting backstory. In AC however, there are quite a few scenes that left me with the impression that some storywriter was just thinking "oh, let's just throw in some random cameo - the fans will love it".
So after all, I was left with the feeling to have watched some nicely done CGI scenes tucked together to fill a DVD, where Spirits Within at least managed to get me believe that I am actually watching a consistent movie.
Here you go with my 2 cents, don't spend it all on icecream.