"This restaurant is expensive" - Fine "This restaurant is delicious." - I've seen this type of phrasing used as a translation for おいしい お 店, and I think it sounds awkward. We usually just say "This restaurant is good"/"This is a good restaurant", meaning that the food that they serve is good/delicious.

I would put it more strongly than torusan. "This restaurant is delicious" is wrong. The problem is that to a native speaker, it means "I can eat this restaurant itself. I licked the windows, chewed up the menus, bit into the tables and chairs, and they all tasted delicious." Of course everybody would understand that the speaker meant to talk about the taste of the _food_, not the taste of the _restaurant._ I woud just say "this is a good restaurant," "this is a great restaurant," "this is a really terrific restaurant." If I wanted to use the word "delicious" I would add a phrase: "This is a great restaurant, all the food here is delicious."