Lots of good info here ... hopefully I can add to it.
The problem with the Marriott card is the measly 1 Marriott Reward point per dollar earned on non-Marriott purchases. On qualifying Marriott purchases you get 3 MR points per dollar.
As an MR member, you earn 10 MR points per dollar plus elite bonuses at full-service Marriott properties, and I believe 5 per dollar spent at Residence Inn and Townplace Suites. Thus, 1 or even 3 MR points is less than what you earn per dollar at the property. Now, perhaps this makes sense when staying at a full service Marriott property, because you can easily goose your earnings to 15 points per dollar spent as a silver elite member by using the MR Visa for qualifying Marriott expenses. (10 per dollar for the stay, 2 per dollar for the 20% silver elite bonus at full service properties, and 3 per dollar from the visa card for the qualifying charge.)
Silver elite is easy to obtain using the current take 2 promotion listed at marriott.com: stay 3 times to earn silver elite and get two free weekend nights.
I carry the MR card and use it only for Marriott stays, and use the SPG Amex for almost everything else these days, except car rentals. For car rentals, I continue to use Diners because of their superior primary rental insurance.
-David
edited to correct some errors in the program and promotion descriptions.
[This message has been edited by LIH Prem (edited 04-03-2002).]