With the Chase Rewards Card / Perfect Card (they keep renaming it but otherwise it stays about the same), which is an MC, you get a 6% rebate on all gas purchases the first 3 months, 3% rebote on all gas purchases thereafter, 1% rebate on everything else, and no annual fee as long as you make at least 9 purchases (any amount) per year. If you use this card for just MasterCard promos like Hyatt's and otherwise just for all your gas purchases, you're likely to get more net from it than from any points card I can think of (given the programs you prefer to accrue in).

The MBNA Amtrak card has thresholds for doing transfers that you need to be aware of, and the transfer opportunities have changed there in the past. You don't want to accumulate a bunch there and then find out it's either not enough for a transfer or that your preferred transfer destination is no longer available, especially if you have no use for actual Amtrak rewards. Whereas with the Chase rebate, it's savings on your credit card bill every month (the rebate you earn one month applies to your total bill the next month), with no thresholds to worry about.