HU is the only 5 star airline and the service is better, however, they are not as big as the big 3 (CA, CZ, MU), so there will be less frequency.

Business or First is the same product on most route. Most chinese domestic route they'd like to call the front cabin "first" class so it sounds better, it is not to the standard of any real F class nor J class. The same applies to lounges, all the domestic lounge are called First lounge with most of them serving fast noodle as the only hot food. Services and seats will be better between the big 4 cities (PEK, PVG, SZX, CAN), some times you'll even get full flat bed. other than those cities, normally you would expect a A320 or 737 with recline seat with no IFE at all.

Chinese airlines doesn't do multi cities, all domestic flights are purchased and price calculated individually.