I know your question was specific to the lounge and suites, I can't help you there. What I can say is, I agree with the previous posts that the Sheraton, while modern is not in an ideal location in DT. Not much shopping around the area, and a little far from most attractions. Good for conventions, not so much for a visitor.

My vote goes to the Westin Bayshore if you want to use SPG. Older property but renovated. Awesome location next to the water. Some of the views there are spectacular.