Below are all my personal opinions:
Points, miles etc are all variable in value. Depending on your travel, a mile could be less than 1c or more than 1c.
Cards that have tiers for cashback are also dependent on your ability to spend in to reach the top tiers. Depending on your annual expenditure, it may yeild you less than claimed percentage (they always claim the top number).
My requirements are:
* Accepted everywhere. I want to use only one card (less headache)
* Rewards are of a fixed and predictable monetary value
* Gives me protection of a credit card, and is on my side (=> No Discover)
* No Annual fee, unless the extra rewards pays the annual fee
* I don't carry a balance, so I didn't see interest rate
My personal choice is Citibank Dividends MasterCard-
* 5% cashback at gas stations, supermarkets, drugstores [offer never expires]
* 1% cashback on everything else [offer never expires]
* No annual fee
* Almost anybody who takes credit cards accepts this (unlike AmEx)
* $300 annual cap for cashback (I have two cards just in case I hit the limit)
* Citibank has taken my side the few cases I had problems with a purchase
Dollars is the ultimate points program. It doesn't expire and you can convert it into anything you can think of!
~T