Incredibles has a 97% fresh rating at RT, with an average of 8.2 out of 10, not sure why you’re thinking reviews were less than stellar. I don’t know anybody who saw it and didn’t love it, very high on the must see list for the nerd community.
Its kinda weird - most reviews for The Incredibles, from both reviewers and movie patrons, were less than stellar. Now its made out to be really great?
That didn't sound right to me, so I checked - it has a 97% "fresh" rating on Rotten Tomatoes:
http://www.rottentomatoes.com/m/incredibles/
Those are unbelievably good reviews. And not just small-town papers and industry rags, but the NY Times, LA Times, Salon, Rolling Stone, Entertainment Weekly and lots of other places you wouldn't expect to find positive reactions to a deeply conservative film.
I can't speak to movie patrons, but the reaction to The Incredibles from critics was very stellar.