I can explain how the chairman Card works as I used to have one and canceled it because Citibank only Waived the annual fee for the first year on it.

The airport access for chairman Card is provided by Priority Pass So you dont get access to some airlines lounges (CO, NW, DL) like you do with American Express Plat but this 3rd party company runs there own clubs in a lot of major airports. This is the same program they give you if you have the Diners Club Card which costs $95 a year. And Centurion Card($2500)

For the most part both chairman Card and Citi PremierPass Card - Elite Level $75 Annual fee has the same benfits. Both have the same Citibank "Thank You" reward program. Both earns points at the same rate. 1 point for every mile you fly on any airline. 2 points for every dollar you spend at supermarkets, drug stores, gas stations, commuter transportation and parking merchants.1 point for every dollar you spend on all other purchases. chairman Card has no point limit but points can only be redem in equal amounts flown point to spent points just like the PremierPass Card which has 100,000 flown points + 100,000 spending point limit.

Now on the Complimentary companion tickets there are some differnces mainly Citi PremierPass Card - Elite Level you can only buy domestic coach tickets from a company called "Sprint Travel" who for the most parts tickets save you between $20-$50 vs buying 2 tickets direct from the airline without having the saturday night stay requirement. Chairman Card offers the same domestic coach tickets offer but expands it to includes first-class domestic and international first-class tickets. Again American Express Platium Card Internatinal first-class program seems to be slightly better as you can buy your ticket direct from any airlines without having to buy "Sprint Travel" overpriced ticket.American Express promo also does not require a Saturday night stay and does not need to start and end in the USA. So with American Express you can buy for example a London-Paris ticket but not with the chairman Card.

Chairman Card Personal Assistants can help arrange the perfect anniversary surprise party or family vacation - This is the same Diners Club Concierge Service as a matter of fact Citigroup uses the same call centers for both. Again Diners Club is $95 Vs chairman Card is $400

Now for the benfits you get with Chairman Card that no other Citigroup Card gives you but only Centurion Card($2500 Annual Fee) from American Express or American Express Platium gives you.

Gold VIP status in the Hilton HHonors - Same benfit you get from Centurion Card ($2500)

Leading Hotels of the World contracted 20% off of retail price. Both Chairman Card and Platium American Express($400) and Centurion Card($2500) offer this benfit.

On-Demand Air Chartering Privileges - Both Chairman Card And Centurion Card offer this benfit. Not like I think anyone who reads this forum will ever use this service but you still have the option to really over pay for a LA-NYC ticket if you want.

Granteed the American Express Centurion has many other benfits over the Chairman Card but for an extra $2100 a year. But you can get both a PremierPass Card - Elite Level + a Diners Club card for $170 and have more or less all the same benfits as Chairman Card for lot less except first-class companion ticket promo + some minor hotels benfits and an airline chater service.

Quoted from my post on Fatwallet.com