We scored free passes when we checked in so we avoided a cover charge. I'm glad we did decide to use them as the view is spectacular. We went on a Sunday night around 8:30-9 and the place was fairly empty. At the time, the dress code was relaxed as there were people there in shorts and t-shirts.
Their drink list was not extensive at all. In fact, my boyfriend wanted to see a wine list and the bartender told us "We only have three types of wines: red, pink, or white." We ignored his ass and went downstairs to the restaurant where we were able to pick up a few yummy glasses of wine." They weren't cheap by any means but when you consider how much it costs to go up the fake Eiffel Tower at the Paris or to the top of the Stratosphere and get no alcohol then its a good deal.
Overall, its a great view. Just get there early and be on the lookout for free passes.