We just came back from Viking's 12 day tour of China. First, I need to say that we are not generally "cruisers" or tour folks as we like to explore on our own and are pretty active i.e., hiking, etc. However, we booked because we wanted to go to China with the least amount of stress and wanted everything taken care of. All I can say is that Viking did and excellent job of hadling every detail for us. All we had to do was show up at the specific time and place they told us each day.
The cruise itself was on a gorgeous new boat and the food was very good (and we are amateur foodies). The cruise was 5 days and was a bit boring for us the first 2 days. WE'd rather have spent more time exploring ports and seeing local sites up river. However, there were 156 passengers and 200 or so staff so we were very well taken care of. The passengers are broken up into groups of about 25, each with its own tour guide and stays with you for the entire 12 days, sea and land. Our tour guide, Bill, was great and the other passengers felt the same about theirs.
Viking is a luxury type tour and is priced that way so we had fairly high expectations which were actually exceeded. Touring China is 12 days is a challenge and we were pretty much exhausted by the end. Each day is packed and there is very little time to do things on your own. On the entire trip I think we only had 1/2 day on our own and maybe an evening or two. My one criticism is that, strangely enough, the cruise could have been cut shorter to allow more time to explore the ports. Seeing the 7 Gorges dam, the terracotta soldiers and the Great Wall was incredible. It's a shame that "Old China" is quickly disappearing. Unless you get out into the countryside, where most tours don't go, you won't see much of what you see in the movies. This was a great way to get a little taste of China and Viking did a great job. Wish we had more time.