I was a bit concerned about the quality of a restaurant in the downtown Vegas hotel, but Grotto has given me new confidence. We were received by a friendly hostess and seated a nice table overlooking the pool area (night-time). Mark our waiter was very friendly, funny, and helpful. He answered any questions about the menu and was particularly helpful with the wine list, noting several affordable options available from a recent event, not on the list. Service was great throughout the meal and the food was very good. We mostly had pasta dishes, which were all delicious.
I'd definitely recommend it and will go back next time I'm staying downtown.