Come for the view. And the dessert. You won't be disappointed in either.
The Roof overlooks the Temple, which is a very unique, interesting view even for non-lDS folks. We arrived for the last seating of the day, which was at 8:00, but guaranteed a beautiful night view.
The food is buffet style with a huge selection of salads and cold pastas, delicious soups (both the clam chowder and the French onion were outstanding), numerous meat selections that change daily, and a fantastic array of desserts (the bread pudding is not to be missed).
Be prepared for a couple quirks -- being an LDS establishment there is no alcohol, coffee, or tea. They so have sodas.
The wait staff is extremely friendly and accommodating.
While probably not a place I would visit with great frequency, it is worth the price and would be a great place to bring visiting friends and family.