Demetre's is more of a nostalgic thing for me. We like to go there because it's small and cute and well... there's desserts. Any place that feeds me chocolate, and sugar, and caramel, and ice-cream, and.. - you get the point - is A-OK in my books.
As Steph pointed out below though, the food isn't that special. If you want a good waffle you're better off going down to Spin. If you want cake or ice-cream, Demetre's will do.