I have Discover, MC, and Visa credit cards, and use different ones for various reasons, all with cashback award programs. Overall, I like Discover the best except for one thing.
The only thing I don't like about Discover is that it is tiered, meaning that the first X number of dollars you charge only gets 1/4 of 1%, then the next X number of dollars is at 1/2 of 1%, and then you finally get to the full 1%. I do however, sign up for the 5% bonus categories each quarter (once is a while they will also have a 1 month special category also). I then make it a point to use the Discover card if I am making a purchase in the 5% special categoy. Like someone else already mentioned, there is usually a cap on the amount that you can earn the 5% on -- eg the first $300 of groceries might get the 5%, but once you spend $300, then you only get the percentage based on what "tier" you're in, which might only be 1/4 of 1%. You start all over at 1/4 of 1% each year on your "anniversary" date.
I also am extremely impressed with their customer service. Their call center is in the United States, which is a HUGE PLUS for me. Only one time have I ever had a dispute with something I had charged, and that was with Greyhound Bus (who BYW has awful customer service). After trying to resolve it with Greyhound, I called Discover, and asked if there was anything they could do (The dispute was strictly between Greyhound and me). Discover immediately credited my account. I don't know what kind of follow-up they did w/ Greyhound, but I never got charged back for it. I have called several other times with questions, and the customer service has been great.
I also like the fact that when I charge something at
Walmart, Jewel, or Dominicks I can get cash back. I use this all the time, as I seldom go to the bank.
I always use my earned "dollars" to purchase gift cards at a discount -- usually Staples or Ace Hardware, where you use $20 to get a $25 gift card. They also have a lot of popular stores where you can spend $45 to get a $50 card- like Kohls, CVS, most major dept stores, etc.
The Visa credit card I use is thru Chase Bank; it's an AARP rewards program, and get a straight 1% back on all purchases. I use this a lot for purchases that Discover does not have the 5% bonus for. I have called their customer service a few times with questions, and their customer service seemed very good, and I believe they were also in the US.
I also have a few Master Cards that I've had for years, but now only use them occasionally for small purchases, mainly to keep the account active. Their customer service is outsourced, and I have had big problems with their representatives every time I have ever called.