Embarkation and disembarkation was smooth and organized. Not much waiting around. In general the service component was top notch everywhere on the Millennium. The Captain of the vessel was friendly and frequently seen visiting with passengers.
The ship was spotlessly maintained with crew constantly wiping things down and cleaning. They were touching up paint where there were scuffs in the halls, even though we were told the ship was being refurbished in a couple of months. Our steward came in 3x/day to clean our cabin and leave fresh towels.
We were warned not to bring bottles of liquor on board, but after the wine tours the staff said nothing if you came back on board with a bottle or two. We expected to have it taken away, but it just went through security and came out the other end without comment. This is unofficial and you won't get any Millie staff to discuss it, but lots of passengers did it once they found out. Bonus!
The food: Main dining room was adequate and edible, if not distinguished. Corners were being cut in food, the portions were small, the chicken dry, and the meat was generally tough. Fish was a safer choice. The exception was the New Zealand lamb - fresh, tender, and delicious. We were spoiled by previous Celebrity cruises. Under Michel Roux, the previous Celebrity executive chef, Celebrity food was marvellous even in the main DR. We ate one night in the specialty restaurant, Olympic, and it was a definite step up, except my food arrived cold due to the waiters being too busy to serve it on time. Book the Olympic on-line before you cruise or you won't get a reservation on sea days.
The bad: Due to the size of Millennium it doesn't dock on the international piers or cruise ship piers, it docks at the container piers in many ports. Often the view is less than inviting at these piers with piles of containers, warehouses, train tracks, etc. For example in Wellington it was raining hard, and the pier was a long walk from everything. There were tracks on the pier to dodge, and huge puddles of water so you couldn't avoid getting your feet and legs wet. Everyone got soaked getting back on board.
Our stateroom (see below) had some problems. But the room was a good size and there was lots of space to store our things. There was a good safe. The quilted bedspread, bedskirt, stuffed headboard and curtains were very old and frayed. I wasn't sure they were very clean, and tried to avoid touching them.