After 30 years of business travel, I have just one remaining unshakable belief: Membership in an airline-sponsored airport club is the single best investment you can make in your own comfort, productivity, and sanity on the road.

For just a few hundred bucks a year, you get access to private hideaways outfitted with comfy chairs and sofas, televisions, desk space and office equipment, a bar and snacks, a place to stash your coat and luggage, and even conference rooms. You can wait out delays, canceled flights, and missed connections in comparative peace and quiet. Airline agents are on the premises to help with flight arrangements.

I can’t think of a single reason for any frequent business traveler not to belong to at least one network of clubs. They have no downside and the public alternatives—crowded gates and jam-packed bars—really have no upside.

But how do you pick a lounge network from among the systems operated by the nation’s six traditional nationwide carriers? Simple: Join the one run by the airline you fly most frequently, which will likely have the most locations at the airports you use.

Don’t fly one airline more than another? Then consider the finer points of each network that I’ve outlined below. Or take a membership in Priority Pass, the multi-airline, transnational system I wrote about at length last year.

Admirals Club
Operated by American Airlines, the Admirals Club has outposts in 38 airports around the world. The new Admirals Club lounge in the American Airlines terminal at New York’s John F. Kennedy International Airport is visually stunning and spacious; the other clubs around the system are serviceable. Best perk: The lounges in the U.S. and Latin America offer free WiFi access. Biggest downer: The domestic clubs charge for alcoholic beverages. Admirals Club members may also use clubs operated by Qantas, the Australian carrier, but only when they are flying that airline. Depending on your status in American’s AAdvantage frequent-flyer program, a new annual membership costs $300 to $450 a year or 45,000 to 75,000 AAdvantage miles.

Crown Room Club
Delta Air Lines’ Crown Room Club lounges can be found in 34 airports, most of them in the United States. Crown Rooms are blandly efficient, but the drinks are free in the U.S. locations. You’ll pay for wireless access, however. Best perk: reciprocal admittance to the club networks operated by Continental and Northwest airlines when flying with them. New members pay $250 to $450 a year or 40,000 to 80,000 miles, depending on your status in Delta’s SkyMiles frequency program.

Presidents Club
The Presidents Club network run by Continental Airlines spans 20 airports. Generally speaking, Continental’s clubs are the best-maintained physically and I’ve found them the best-stocked with complimentary newspapers and magazines, snacks, and beverages. Many clubs have discreet “family rooms” outfitted with televisions and other diversions to keep young travelers tranquil. U.S. Presidents Clubs also offer free WiFi access and free alcoholic beverages. Members also receive admittance to the Alaska Airlines, Delta Air Lines, and Northwest Airlines club networks, on days when they’re traveling on those airlines. The annual fee for new members is $350 to $450 depending on your status in Continental’s OnePass frequent-flyer plan.

Red Carpet Club
United Airlines’ Red Carpet Club network covers 34 airports around the world. United has supplemented its own locations with day-of-travel privileges at clubs operated by Air Canada, US Airways, and international Star Alliance carriers. But the years since United’s 2002 bankruptcy haven’t been kind to the Red Carpet Club system: United has cut back on in-club amenities and members routinely grouse about the skimpy snack items and the paucity of newspapers and magazines. Members also pay for WiFi access and alcoholic beverages at the U.S. clubs. Annual fees for new members run $300 to $500 or 40,000 to 70,000 miles; the price is determined by your status in the Mileage Plus frequent-flyer program.

US Airways Club
Years of penny-pinching and cutbacks after the 2005 merger with America West Airlines have reduced the US Airways Club system to just 15 U.S. airports and an outpost at London’s Gatwick Airport. Many lounges have threadbare furnishings and notable cleanliness issues, but some do offer free WiFi access. US Airways also has an a la carte pricing system: Depending on their status in the Dividend Miles program, new members pay $315 to $390 for annual membership. Day-of-travel privileges at United clubs cost another $120 a year and similar perks at Star Alliance lounges cost another $100.

WorldClub
Operated by Northwest Airlines, the WorldClub network is probably smaller than it should be (in just 18 airports globally), but members also receive admittance privileges at clubs operated by Continental, Delta, and Alaska airlines and the international SkyTeam Alliance when flying on any of those airlines. Members get free WiFi at most clubs and free drinks in the U.S. clubs. Another nice perk: free use of semiprivate conference rooms. Annual fees for new members range from $250 to $450 depending on their status in the WorldPerks frequent-flyer plan.

The Fine Print
Alaska Airlines runs a small network of clubs called the Board Room at a half-dozen West Coast airports. And Air Canada operates the Maple Leaf Club at many Canadian airports. Almost all of the clubs allow members to bring two guests into the lounges free of charge; they also offer complimentary alcoholic beverages at their international locations. And remember that a standard perk of international business class or a first-class ticket is a one-time free admittance to a private lounge at your departure airport.  

One final thing to keep in mind: If you’re an American Express Platinum cardmember, use the Airport Club Access Program. If you pay for your ticket with the card, you receive access at some clubs run by American, Continental, Delta or Northwest airlines. And if you’re packing Amex Centurion—that’s the black by-invitation-only card for superspenders—you receive a free Priority Pass membership to more than 500 clubs around the world.