Hi midknightbass,
I can see you have made up your mind, but let me give you an opinion on the Yangtze River Cruise.
A lot of riverboats were built for the Three Gorges Cruise which was a great sight through forested gorges and the wide river plains with visits to ancient villages which relied on farming for millenia, In that regards it somewhat was similar to the Nile Cruise you were on.
Today these are specially built river cruise boats in search of customers. The gorges are filled to the point the "ooohs" and "aaaahs" are now somewhat muted. The deep gorges are gone, filled with water. The archaeological sites, ancient villages and farms are gone. They are under water. Rather than see and learn about the history of this great river, now you float on a lake and visit relocated villages with politically-slanted tours on how nice the relocation of millions went. They do not tell you the people no longer have farms on which to work. The history of their family lineages as farmers is broken You also get to see the wonders of the dam engineering. . This is not your barge tour of Europe or Nile tour of Egypt. This is floating on a recently filled reservoir.
If you travel from Shanghai you see very little of general interest except a lot of industrial uses of the river. This is a "working river" with major ocean-going shipping vessels plying the waters. If you must take the tour, take the northern end from Chongqing to Yichang or, if essential, Wuhan. The best times are spring and fall, late April to early June and September through mid-October. Summers can be very, very hot in the cities on the Yangtze. Two major Chinese holidays are in these periods, May 1-3 Labor Day and Oct. 1-7 National Week.
One reason I am saddened when people take these cuises is that there are so many wonders to see in China and spending three or eight days on this river, while relaxing for sure, is absolutely nothing compared with the history and natural highlights of this fascinating civilization going back over 3,000 years.
In two to three weeks, you should see Beijing for four days, Shanghai for two days, Yangshuo/Guilin for a couple of days at least for rest and relaxation on land, Jiuzhaigou National Park for awesome creations of nature for at least three days, Lijiang for two to four days to live in "old" China and see more beauty, nature and daily life in rural areas. Some other places include Xi'an with the terra cotta warriors, Suzhou for the finest collection of world famous Chinese gardens, Chengdu for the famous Leshan Buddha as well as the Pandra Breeding Center, and on and on.
Tours are not the best way to see China to spend time and linger where you have keen interests, but they will provide you with company. Unfortunately they also give you forced shopping stops every day (at higher priced places where the tour guide gets the commissions), and speed-tours of some very famous places (some cover the Forbidden City in one hour).
Of course, if I had a choice of China with Yantze River Cruise and organized group tour or no China visit at all, I would pick the tour!