If you don't expect to fly NW/DL, or you don't expect to be using airport lounges more than 10x a year (or bringing in guests more than 10+ times a year), I'd recommend getting the Citi Plat Amex instead.

With the Citi Plat Amex, you get Priority Pass membership and 3 free lounge visits for you alone (unrestricted in terms of boarding pass); each additional visit (you or guest) incurs a $27 charge. You also get a similar domestic complimentary airline ticket deal (no int'l though), and access to a benefit quite similar to the Amex FHR. Unfortunately, NW/DL lounges are leaving the Priority Pass program.

The Citi Plat Amex has an annual fee of $125 (actually, I think it's $99 now!), compared to the $450 Amex Plat fee.

For me, with my erratic travel behavior that only averages 10 flight segments a year, it actually makes more sense to just go with the Citi Plat Amex. Besides, the Citi Plat Amex grants free continuous annual membership to a credit monitoring service (I don't believe the Amex Plat does this).

More info here about the recent added benefits to the Citi Plat Amex:
http://www.flyertalk.com/forum/other...rivileges.html