I'm a fan of the Shrek series. I didn't gripe when I heard they were planning seventy-five more. And I enjoyed watching this, though with a feeling of mild disappointment.
But oh, lord, it SO reeks of retread. It's sad when such an excellent property is let down by uncreative storytelling. They need some new writers down at Dreamworks, badly.
EDIT: I rewatched, and maybe I was a bit unfair with the review. The movie is still full of funny stuff and a reasonable entry into the Shrek series. Making Arthur less of a stereotype and giving Shrek a storyline with some real teeth in it might have made this a great film.