I would suggest that you look at Victoria very carefully (and cautiously). Except for the suites at the front of the boat, the cabins are very small. They recently added balconies, by just hanging them off the sides of the boat. We had a fantastic cruise upriver on Victoria III before the dam was finished and loved every moment of it. But we'd splurged and booked one of the forward Shangra La suites. As there were no occupants in the similar suite across the hall, we had sole use of the enormous bow terrace which was the width of the boat. Our several day cruise through the Three Gorges was one of our great travel memories.
Unless you like very compact digs, you should likely consider one of the suites on Victoria or one of the cabins on Yangzi Explorer. That looks like a beautiful and spacious boat. I think that Viking's cabins are a lot bigger than those on the Victoria boats, as well.
In any event, a cruise on the Yantze is a very special trip.