Domestic US lounges, eh. They're better than the terminal but not worth going out of your way for. Exceptions are the Amex Centurion lounges and certain lounges run by foreign airlines, like the OneWorld first class lounge at LAX run by Qantas—cook-to-order food, full bar, nice showers, etc. All complimentary. Good tacos.

Internationally, it's a different story. At Lufthansa's first class terminal in Frankfurt (yes terminal, not lounge) you have private security and passport control and get driven to your plane in a Porsche across the tarmac. Thai Airway's first class lounge in Bangkok has complimentary sixty minute massages (not that kind). Cathay Pacific's lounges in Hong Kong have full cook-to-order restaurants, foot massages, etc. all complimentary. All Nippon's first class lounges in Tokyo have 17-year-old scotch just sitting out for whoever wants it. Japan Airlines offers a sushi bar—with the sushi chefs right in front of you—and complimentary massages.

Not a bad way to travel. So far I've managed all on award tickets.

For the most part, Western lounges just feel like hotel lobbies, but with free booze and buffets. Significantly quieter than the main terminals, genuinely helpful staff, clean bathrooms, etc.

Great if you have access, but nothing I'd go out of my way to pay for.

One exception: Showers. Holy hell is it an amazing feeling to take a shower half-way through a 20+ hour itinerary. Worth their weight in gold.

They have good food and alcohol. They also have unusually nice fellow passengers that are worth talking to.

A friend of mine took me into airport lounges a few times, and they were all pretty nice experiences.

It really depends. In the USA, the biggest benefit is that you can set your bags down and go to the can without worrying they are going to get stolen or carted off by bomb disposal. Also, you get free WiFi.

In other countries, airports tend to be more spartan, and the lounges nicer. Many of the Asian carriers offer sushi, noodle bars, top-shelf drinks, and showers.

The one in the video (IST) is actually very nice, there is lots of space (especially compared to the rest of the airport, which is usually very crowded), free food and drinks (including alcohol and decent, non-drip coffee).