My favourite is the Hilton Riverside too. Great staff, stunning view, rooms are well kept, and the lounge is my absolute favorite. Breakfast (ground floor) is very good too. You can often get it for Sub-500 RMB rates, which is a total steal (especially as Elite)

However, the location isn't very much in the centre.

I've stayed in quite a few hotels in NKG before.

Sofitel is solid, and used to be relatively cheap (prices went up) - was a bit angry at them last time, when they renovated the pool without further notice and it was closed all the time, but that was just bad luck. I didn't liked the breakfast at the Sofitel too much.

Sheraton is the second-oldest city hotel. A bit worn out by now, but location is VERY central.

Jinling hotel is great if you want to stay in the absolute centre, has history, and the best Baoze (for like 3 RMB)

Apart from that, plenty of new hotels all across the city.

The only hotel I can't recommend at all is the Hilton Wanda Plaza. It's NOT very central and I've had two really bad stays there.