MC2 is not your average hotel restaurant. Typical hotel restaurants ( and this Marriott has one in its sports bar ) offer mediocre food, average service and the convenience of on property dining for hotel guests.
MC2 is actually worth coming too, even if you are not staying at the Cambridge Marriott.
The menu is eclectic and the portions delicious and generous. They offer the option of "small plates", tapas size portions which make for a tasty meal. I ordered a salad and 2 of these small plates, and could not finish my meal.
Dessert options are limited, but creative. I enjoyed the caramel ice cream berry brullee which was a toasted ice cream and berry creation in a large ramekin.
They participate in Restaurant Week and have an impressive fixed menu, which we did not try, but looked good.