Actually, as long as the hotel is not a Resort property, Golds will get lounge access and free breakfast. The JW Cancun's Club 91 is not a normal "lounge" and even Plats don't get into that one. Everyone has to pay if they want in there.

As for really nice hotels and lounges, I would first mention that most lounges outside of NA tend to be a little nicer, have more food, and quite often are open on weekends. Some even have free booze. I have stayed a few times at the JW Shanghai. I was very impressed with the hotel itself, its location, the room upgrade I received and the hotel's lounge. There is a thread or two in this forum that can provide you with a lot of details, but a few items of note are that it has what is billed as the "highest" library in the world. You go to the very top of the hotel and there is small library of books. There is even a "secret" passage that will take you outside and give you one of, if not the single best, view of Shanghai (short of actually flying over the city.) The lounge was large and had a very nice selection of foods. You could probably have a full dinner there if you wanted to. And I was upgraded to a very nice multi-room suite the two times I have been there. (Though I was a Plat during both stays and they were short one or two night stays.)

Oh, and what is nice is that if you are using points, most of the China Marriotts are mid-range category (i.e. 4's and 5's rather than 6's and 7's). So your points go farther.