- Drinks - nearly all the lounges have beer, wine, champagne, and some of them have mini-bars with liquor. Then there's always soft drinks, juices, coffee, and water. It's all free so drink up as much as you can before your flight. Maybe if you're drunk enough the flight will be bearable. Plus it beats paying for drinks at the airport bars. Something else you can do (that isn't exactly allowed but I usually do it) is put a few bottles of beer into my carry-on and take them on the plane. SSHHH don't tell anyone I gave you that tip!
- Internet - It's pretty obvious the benefit of this.
- Shower - I've never used this but if you're traveling all day for long periods of time I would consider using them.
- Food/Snacks - Besides Chex-Mix, crackers, pretzels, and gold fish, sometimes they have mini-sandwiches and hors d'oeuvres. Again, this is free food, SO EAT UP! Much cheaper than buying food at the airport.
Those are the benefits I know of. Any others you can think of add them to the list...