Locoweed and dmccarty, how long ago did you have a problem with Discover? I've been using a Discover card more than any other since 1987 and have had no complaints with them in 27 years. Twice in that 27 years, charges that were not mine showed up, I called, they removed the charges, promptly sent me new cards with new numbers, and a letter for me to sign if I'd be willing to help prosecute if the culprits should be apprehended, which of course, I'd be more than happy to do.
Only one time in my life have I had a credit card refused. I filled up with gas in Georgia once in 1993, went inside to pay, and they said my credit card was refused, so I used another card. Then when I got home I checked and found that my limit was set lower than I had thought, and even though I paid in full each month, I had bought a new computer and a bunch of other stuff that month that ran the bill up high. I called and apologized for going over the limit and the guy just laughed and said he'd just raise my limit so it would never show that I'd ever gone over the limit.
I'm one of those characters who actually keeps my receipts, matches them to the statement, pays the bill, and keeps those statements and receipts at least 5 years. I also go to my credit card company websites 2 or 3 times during the month to see if there are any charges I don't recognize.