We took a 5 day pre-cruise to China followed by by a 23 day cruise that included CHina, South Korea and then on to Alaska and ended in Vancouver.
The land tour included going to Xian China to see the Terracotta Warriors. This was the highlight for us. Until you see those for yourself, you cannot appreciate how awe inspiring these are.
Our impression of China was pleasant as it was cleaner (except the air), more modern and friendlier than we expected.
Now on tho the Cruise itself aboard Diamond Princess. It was really Good. The staff were very helpful and efficient. Friendly happy staff was the order of the day. We would sail on the Diamond again.
Although we enjoy "At Sea days", because the crossing over to Japan was cold and gloomy, it wasn't pleasant to be on deck or the balcony, so the interior activities were more crowded than normal and after 8 days (you X dateline and add another day) got real old. Too bad they couldn't sail lower in warmer climate, but they take the Great Circle route which is all very North and the Bering sea.
We did experience something not scheduled. A passenger was very ill and need to be airlifted to a hospital. The ship found a port in the Aleutians that had an old WWII airstrip that was still maintained and they arranged a medical evac there. That was all done within an hour and too bad it was 11PM and so dark, we couldn't see much. But it is comforting to know that the ship made that extra effort when needed.
All in all this was an amazing cruise and We loved it. So yes, we would cruise the Diamond Princess again.