We booked the Xmas lunch because so few restaurants open on the 25th, and it worked out really well.
We went for the 85€ Christmas day lunch, which comprised of 5 quite substantial courses and coffee to finish. Pretty good value especially as the few places that open use it as an excuse to charge 2 or 3 times the going rate.
The service was first class, attentive but not pushy, with non of the falseness that some places direct at non Italians.
My only complaint is the markup they charge on the wine, not so much on a glass which is around 9€, but we had the Livio Felluga Terra Alto which is about 45€ retail and they charge 120€, nearly three times retail!
Still, it didn't spoil the overall meal, and would definitely come back.