Ratatouille really spoke to me when I first watched it. I think I was cooking butternut squash soup for some friends at the time, and it was the first Pixar film I'd watch when, I guess, I wasn't age appropriate (I was about 15/16) . I really enjoyed it, it was a quirky film that didn't follow traditional routes and gave you something new to get your teeth into. Rats aren't often painted in the best of lights, so this was entirely enjoyable piece of anthropomorphism that put some character back into a badly used rodent.
I think the ending was a little more brave than usual, which was enjoyable, especially for a slightly older crowd, with age-old disney well and truly owning the "Happily Ever After", so modern day animation films need to press the edges of the box to get a satisfying finale - and Ratatouille performed.
There were a couple of slower moments in the middle, which I think might lose the engagement of younger children, but all in all Ratatouille was a great film that I do watch sporadically if not regularly.