Hi Andy,
Yes I did do the Yangzte cruise.
I was on single supplement with TS so got my own cabin. I would expect your own cabin with JY. Clean & comfortable with 2 single beds & a balcony out to the river. It would probably be a bit cramped for a couple with 2 cases etc but for one on their own it was fine. Anyway you don't want to spend your time in the cabin!
My only real "experience" of cruising was on one of the large cruise ships out of Southampton where "We're only here for the beer" is the order of the day! This was altogether different as everyone wanted to experience the river and the gorges. Yes there is a bar and entertainment in the evening but this is peripheral to the main experience. The crew were lovely and doubled up as the evening entertainment. OK they would probably get nowhere on BGT (which is arguably in their favour!) but they did put on some good fun entertainment.
Meals, apart from breakfast, are Lazy Susan style & plenty to eat. There was one evening where you could dress up - one or 2 guys bought suits - but smart(ish) casual is generally fine.
There are plenty of viewpoints to watch the river go by and there are a few talks put on by the crew.
There are a variety of onshore excursions - some are included & some you have to pay for.
Shore excursions included the 3 Gorges dam but it was raining and we did not see much. There is also a visit to a reclamation village (where locals were relocated to after the flooding caused by the dam) which was good as you got to meet and mingle with the locals. I took advantage of all the included excursions - they are enjoyable but also give you a chance to stretch your legs.
There is also a laundry service & tea/coffee in the room.
Anything more specific then feel free to ask.
Also, unlike being at sea - you hardly noticed you were moving.
Cheers, Ian