Are these sentences grammatical and natural?
▪ He is praising it (a food item) out of proportion. I wonder if he got cash for that! It's not as tasty as it hyped up to be; moreover their behavior with customers is awfully disgusting. They give preferential treatments to their local customers;I mean they don't maintain the "first come first serve" basis. In total, if I were to give ratings I would give it one in a five scale.
P.S. I don't have a motive to discourage you for tasting it. You can try it. It can be a new experience though. Who knows you might like it. After all everyone has their own tastes and preferences.