The biggest perk you're getting, most likely, is the access to the airline lounges. If you travel a ton + travel on different airlines then this may be a good card for you.
Think about it this way. Delta club = $400 a year, United/Continental club = $300 a year + another $400 a year for the American Airlines Admiral club.
Or, you could get an AMEX Platinum, which not only gets you into the same clubs that this one does, but you also get $200 in "airline fees" back - effectively discounting the price of $400 a year in half, so you're only paying $200 a year for the airline clubs.
It really, really depends on your travel schedule.