We came up here on a weekday night to check out the view of the city, and boy is it a good one. The drinks are quite expensive, but come during 2-for-1 happy hour and it is well worth it. The lounge seating is nice, with a variety of table and chair setups to accommodate whatever group dynamics you might have. The rest of the observation tower closed at 1 am, so we decided to come up to level 107 since it is open until 4am. If you want an amazing view late at night, this is the place to come.
Other people have mentioned that they hold strict to a 2 for 1 per person rule, but maybe that depends on the bartender. A friend and I had no problem ordering two at a time and each taking one and they didn't say anything. Or maybe they just knew that we were going to be drinking a lot so it didn't matter.
The bar here had a much more luxurious feel and swanky vibe than the hustle and bustle on the strip 107 stories below. I'll be sure to come back here when I find myself in Vegas again.