My experience in more than a half dozen visits over time is that downstairs usually has EVERYTHING upstairs has, but also has many other items not available upstairs and greater variety and selection, especially in the area of fresh juices. Upstairs has a better view (but only in the very back) and the service tends to be more personal and quicker. Sometimes check-in will say that breakfast can be either upstairs or downstairs for Platinum guests, but other times not. Breakfast downstairs is sometimes included in the rate, other times not. I don't know what the general policy is, or even if there is one, but based on past experience I would choose downstairs without hesitation. Of course, on any given occasion experience may vary due to the timing of restocking or other staff actions. Furthermore, the front desk people often seem to be trainees or not really sure of the information they are providing. In any event, in my opinion the hotel is absolutely spectacular, Platinum treatment is excellent, and both breakfasts are among the best offered by any Starwood hotel anywhere.