I've never been one to carry many credit cards. For me, just a couple of major ones are all that I need. Just in case there is a problem with one, then I still have the other.
I've been a Discover card holder for about 5 years. From the very beginning, I was impressed with them. They were the first one that I was associated with that offered rewards for shopping. They offer higher rewards for specific categories during various times of the year, such as travel, restaurants, gas, clothing and appliances, just to name a few.
At first, I would always have the cash award credited to my account. But after looking at some of the companies they partner with, I finally realized I'd get more if I chose a gift card. For example, a $20 cash bonus would be worth a $25 gift card at Land's End, Red Lobster and dozens of other places. I hesitated at first, not sure how it would work and if it would be a hassle, but finally tried it with a Red Lobster gift card. There was no problem at all.
Discover offers you the choice of cash, a credit to your account or a gift card. By far, you get more for your money with a gift card, but if your balance is high, it's tempting to use the reward to pay towards your balance. I've done it both ways.
Just recently, Discover (and/or their partners) changed the rewards program. They require a $20 minimum cash back balance before you can do anything and now they have increased it to $40 for many of the gift cards. That disappointed me as I had hoped to get another free meal at Red Lobster, but instead chose to use the money to go towards my balance.
Discover is my favorite credit card. I don't pay a fee to have it, pay the balance in full each month, pay online, so I don't even use a stamp, plus I get cash back. Basically, they pay me to use their card and I am more than happy to do it.