Il Mulino at the Swan is the best for overall Italian food. There just isn't a comparison to the others.
Best Pizza is Via Napoli in Epcot. Tutto slides in at third overall. Portobello gets decent reviews on the boards (I have no idea why), but we went two years ago and won't be wasting time or money there again. I seriously thought Chef Boy R Dee was better tasting, and the service was terrible to boot. Mama Melrose got it's shot last year for the Fantasmic package, and it was a joke. The only 'Italian' restaurant we haven't tried in recent year's is Tony's, but as I recall from way back, there was no reason to revisit it.