Without a doubt, the St. Regis, both for better service and location.
The Great Wall is the first foreign owned hotel in China, and is showing its age. I generally don't care much for the Sheraton brand in Asia. It's a tarnished name there..... (see the complaint thread regarding Sheraton TPE, and I must say.....I TOLD ALL OF YOU SO to stay away from that property after I saw a cockroach in the Lobby Cafe while having evening snack)......
