I loved his paintings of the Yorkshire Wolds, it's an area which doesn't appear on any major tourist trail, it's not spectacular National Park, it's just average, typically English, agricultural countryside, but his paintings ooze love for it and the intimacy of his studies of seasonal change are delightful.
There is other stuff, like Salts Mill and some great (ipad) paintings of Yosemite, and earlier work in California (including Grand Canyon), which are impressive.
Some people were wandering round muttering negative stuff like "he's not a Constable is he?". Well if you want Constable go and see him, Hockney is different and thank goodness!
The only negative point I would say is that it was very crowded, why can't the galleries work out that these things are going to be tremendously popular and put them on for longer and extend the hours at an early stage?
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC