My wife and I have cruised on Celebrity three times before and while the Millennium is a step below the Solstice class ships in many ways, we still had a wonderful time on her. We choose this cruise from it's unique itinerary that traveled from Hong Kong to Taiwan, Nagasaki, Busan, Jeju, Beijing and Shanghai.
Embarkation: We seemed to time our arrival very well and had only a 10 minute wait on the Select/Elite line before getting to the window. However, we saw the monster line for other passengers, many of whom advised us they waiting for an hour or two to get to the desk. This was the last time Celebrity will be using the Ocean Terminal because the new terminal at Kai Tak is opening in June.
Cabin - We had an inside cabin which was okay. The storage in the room was not quite as plentiful as on other ships and they could have used an overhead storage area over the bed to make putting clothing away a bit less cramped. Everything worked as it should and the room was quiet and dark at night which is great for sleeping. The room attendant Eddy was outstanding and attended to our every request quickly and enthusiastically.
Food - Overall we were pleased with the food in the main dining room. While the quality and temperature of the dishes were not always top notch, by and large our dining experience was enjoyable. Select dining was a bit frustrating early in the voyage with limited reservation times available and walk up wait times of 30 minutes, but that issue seemed to be resolved after a few days and went much smoother afterwards.
The Oceanview Cafe had all we needed for breakfast and lunch. The waffles/french toast are a bit hidden at the back (aft) of the cafe so make sure you make a full lap your first day there.
We had one remarkable dinner in the Olympic that was well worth the $45pp cover charge. We skipped the other two restaurants (Qsine and Bistro on 5) that we enjoyed on previous cruises because we were content with the main dining room.
Entertainment - Steve was the Cruise Director and was the best we've had the pleasure of meeting. He was very personable and generated good will where ever he went and he went from early morning to late night to every venue. The shows were divided between the three production shows (sub par) and the guest performers (very good). They also had a very enjoyable speakers for their enrichment program including Jim Kennedy who wowed the crowed with 4 lectures about the space program and his personal lessons learned from it.
Shore Excursions - We did not use any of the ship's excursions. All our tours were arranged via the roll call on Cruise Critic.
Taiwan - We skipped Taipei and arranged with another couple for a driver take us to some nature areas. Most memorable was the food which was both delicious and cheap. Don't miss the night market.
Nagasaki - We arranged for a free Goodwill Guide. Tetsuya is a 71 year old guide that we could barely keep up with. He took us all around town, seeing the peace museum, the mountain overlook, some temples and even stopped off at his home to introduce his family. The Peace museum is very moving but is not for the faint at heart.
Busan - We did it on our own. There is a city bus a block from the pier that will take you into town. Most memorable was Shinsegae Centum City which is the world's largest department store. It's very upscale including a skating ring, multiplex theater and a four floor golf driving range on the top floors.
JeJu - We had a driver with another couple and explored the Tea museum, some nature sites and the mystery road. Most memorable was the Alive Museum which has 3D art that puts you in the painting proving you have a friend with a camera.
Beijing - We were with a private group of 115 that did a three day tour including two nights in a hotel in town. Beijing is almost 3 hours from the port and traffic there is always bumper to bumper. There were many memorable sites we saw including the Olympic stadium, Summer Palace, and some temples but clearly you should not miss the Great Wall and the Forbidden City.
As for Hong Kong and Shanghai, both are amazing cities. We spent a few days before and after the cruise to explore them and had a great time.