What is the best airline reward credit card?

I want to apply for a airline reward card. But my friend tell me that American Express provides the best airline reward cards. Is he right? if he right then which is the best airline reward card provided by American Express.

I use the American Express Blue card and Happy with it. You can use it for flights on any airline including Hotels, Cruises and Rental Cars.

Every 7,500 points you earn can be redeemed for $100 off any flight, hotel, rental car, or cruise. If you find a flight for $100, then you can get a free flight with only 7,500 points. If you find a flight for $200, then a free flight will require 15,000 points. The savings are unlimited.
The Chart 1 point = $1.00 dollar
75000 points =$100.00
15000 points=$200.00
22500 points=$300.00
30000 points=$400.00
And so on..