i had the same experience as premex... as a diamond, i was pre-assigned a spacious towers level room. the towers lounge offered a fairly extensive selection of food and snacks throughout the day - and a very well-stocked, help-yourself fridge filled with soft drinks, water, etc. the entire staff was very pleasant and helpful. overall, it's one of the better run hiltons - with great towers lounge.

it is a busy convention hotel, however, and if there is a big one in town, your mileage may vary with regard to upgrade opportunities.