But not all of them are equal. I am using the Citibank Dividend and the Discover Cashback card. The Citi card used to give 5% (now 2%) cash back for gas, grocery and 1% for everything else, with an annual limit of $300.
The Discover card is more complicated. It has a “ladder” rate and does 5% promotion every three months. Each year (start from the day card being activated), it gives 0.25% for first $1000, 0.5% for the second $2000, 1% for anything afterwards. Every three months or so, e.g., Jan 1 to March 31, it gives 5% cashback for airlines, trains and buses; and the 5% category could change to restaurant from April to June. Also Discover has more redeem options, in addition to cash, it can be converted to gift cards from various vendors.