My wife and I have done 5 river cruises so my opinions are more comparison based than usual (forget the stars since my rating is against many similar others).
We started by arriving in Shanghai three days before the tour (land + cruise) started. Obviously after a long flight rest is needed. We got in a little shopping and took one tour on our own. I've got to say that that tour was a significant highlight of our memories. We did the half day Water Village tour and thoroughly enjoyed it.
The organized Viking tours are well conducted with both your assigned Viking tour leader (for the duration) + a local guide (superfluous except for political connections). They include much bus travel through extreme traffic to the point where you want to get off and walk. Obvious shopping stops are made at factory outlets which were very interesting to learn how things are made.