We had a great time on our first cruise holiday with our 11 month old son.
He loved the attention from the great staff and we loved the food and attention from the great staff. Nothing seemed too much trouble and even though we had the lowest grade cabin, we didn't feel any different from the more expensive cabins.
The facilities provided for children were great and we enjoyed the relaxed nature of the ship, not too big and not too small (at 77kt!) You could still find quiet areas of the ship for yourself even though there were 2500 people on board.
Space fine even with cot. Very quiet, but being high up meant we had a bit more movement in Bay of Biscay, up and down...