Earning rewards is one of the biggest advantages of using a credit card instead of cash, and cash back is one of the smartest reward types. Cash back literally means that you receive a certain percentage of the amount you spend back as a rebate, either in actual cash as a check or bank deposit, or as a statement credit.

But the results of the latest Capital One Rewards Barometer show that changing categories are not for everyone.

In fact, 54% of survey participants just want to be able to earn a fixed amount of cash back, no matter what they buy. 15 percent of card users surveyed even went as far as citing changing cash back rates as a complaint.

That makes sense because knowing exactly how much cash back you will earn on your monthly spending makes it easier to calculate savings and work them into your budget.

Another 30% of consumers say that they want to earn unlimited rewards. Many cash back credit cards limit the amount of spending for which you earn cash back. Being required to collect a minimum amount of cash back "points" before they can redeem was an issue for 27% of respondents, and hidden charges also got cardholders' goat, with 17% citing hidden fees as a complaint.

So is a flat-rate card that offers unlimited rewards really the best? We at GET.com felt this was a question worth answering.

  1. Flat-Rate Cash Back Credit Cards

    Flat-rate cash back cards let you earn anywhere from 0.5% cash back at the bottom end, to the impressive 2% cash back.

    Many flat-rate credit cards have no caps on the total amount of cash back you earn.

    That means, no matter what purchases you make with your card, be it paying your rent, buying a car or picking up groceries, you will earn that amount of cash back.

    Let's say you run on a budget of $3,000 monthly, and you are able to pay for all of your expenses using your credit card which has a 1.5% flat-rate cash back rate. You can count on receiving $45 cash back every month.

    In short, a flat rate makes for simple, easily countable cash back savings.

  2. Changing Category Cash Back Credit Cards

    When you use a credit card with changing categories, you earn a high amount of cash back on some types of purchases. Most good category cash back cards also give you a flat-rate of cash back on other purchases, though this may be quite low.

    Chase Freedom® is one of the most popular cards with changing categories, and is a good example of a prime cash back credit card. It lets you earn 5% cash back in combined purchases in bonus categories you activate. The catch is that you only earn this cash back on up to $1,500 of purchases in the 5% categories each quarter, and you need to activate the 5% cash back by phone or online every quarter.

    You enjoy new 5% categories every 3 months. The quarterly categories are usually similar every year, which means you can get an idea of what you can save, but there is some variation.

    But you do also earn a flat-rate of 1% cash back on all other purchases, so you can always count on 1% cash back on any purchase. In other words, you get a flat rate, plus the added perk of 5% cash back for some purchases.

  3. Fixed Category Cash Back Credit Cards

    A third kind of cash back credit card that is becoming popular gives you a fixed rate of cash back for purchases in fixed categories. Some credit cards even let you pick the category you want to earn high cash back on from a list.

  4. Which Gives You More?

    It really comes down to how you spend, what you spend on, and how flexible you are. For example, being able to earn 5% cash back on gas, restaurant dining or Amazon.com is fantastic if you own a car, eat out regularly and do a lot of shopping on Amazon.com.

    But if you don't drive, don't eat out much and hardly ever use Amazon.com, then all you will get is the low, general cash back rate. In that case, you would probably be better off with a card that offers a higher flat-rate on all spending.

It's interesting to note that studies have shown that wealthy Americans prefer cash back rewards over any other kind of credit card rewards.

Although the Capital One survey shows that 39% of respondents prefer to use just 1 credit card for all their cash back earning, the GET.com team agrees that using 2 credit cards is the best way to max out your savings.

If you are in a position to manage 2 cards without hurting your credit, then combining a card with changing categories or high cash back in fixed categories with a credit card that gives you a high flat rate of cash back (for all your other purchases) is a rewarding way to work, in our opinion.