It's not easy to compare different credit cards—banks go out of their way to obscure key details, and most comparison websites are difficult to navigate. So I decided to test out BillShrink, the new website that tries to find you the best deal on gas, credit cards, and cell phone plans, based on your preferences and usage habits. It allows you to search for cards based on your spending habits, the kind of rewards you want, and your credit rating. Read on for the full BillShrink review, or simply skim through for the bolded names of credit cards that offer solid cash-back returns.

But it has some flaws. I was immediately put off when I found out that BillShrink doesn't have data on Chase or CapitalOne cards. Both companies have excellent cash back cards, so it's a shame they aren't featured. But BillShrink's CEO, Peter Pham, says he site should have info from Chase up later this week, and he hopes to have CapitalOne cards on it in the near future.

I have the Chase Freedom Card, which has an excellent cash back program. I get 1% cash back for most purchases, and 3% for spending in bonus categories like groceries. Plus, once I've accumulated $200 in cash back rewards, I get a $50 bonus, for a total cash back rate of 1.25%. Also, when I opened the card a year ago, I got a $50 bonus, a promotion that's still in effect. CapitalOne has a similar deal with its No Hassle Rewards Cash Rewards Card: 2% cash back in bonus categories, 1% on everything else.

In my first search on BillShrink, instead of specifying that I wanted a cash back card, I picked the option "Best value (We'll find it!)." I said that I spend roughly $1,000 a month, and pay it off in full. The first card to come up was the Bank of America Asiana American Express Card, with a $99 annual fee. It's for people who want to earn miles on, I kid you not, Asiana Airlines. Supposedly it will save me over $500 a year—which means Asiana Airlines must have a pretty fabulous frequent flyer program. Pham says BillShrink typically estimates that you can redeem 25,000 miles for a $500 ticket, which is equivalent to getting 2% cash back. In my experience, however, that estimate is overly (if not wildly) optimistic. I have exchanged 50,000 miles for a $500 ticket, but never any less.

The second card on the list was an Alaska Airlines mileage card, and after that came one from JetBlue; all three, alas, were useless for me. Within a couple months, BillShrink plans to allow users to search based on which airlines they fly, says Pham, the CEO. But for now it simply offers the best deal, regardless of which airline is offering it.

Next, I changed the filter to look only for cash rewards. The first card that came up seemed pretty good: the Citi Dividend Platinum Select Visa Card for College Students. BillShrink says it offers "up to 5% cash back" in bonus categories, which is great. But when I did a little extra research online, I found out the 5% cash back lasts for only six months; then it's down to 2%. BillShrink knows that and includes it in its calculations, Pham says, but the there's no information about the six-month limit on the site. Nevertheless, a straight 1% cash back is pretty good. Citi has another good cash back card aimed at general consumers: the Citi CashReturns MasterCard, which returns a straight 1% cash back. The card has no bonus categories, but it does offer a 20% bonus the first year you use it.

BillShrink came up with several other good cash back cards, all of which return roughly 1%: The First National Bank of Omaha Maximum Rewards Platinum Edition Visa Card, the Bank of America Accelerated Rewards American Express Card and the Bank of America Efectiva Platinum Plus Visa.

The site has one other flaw, however: to calculate how much cash I would earn over three years ($438), BillShrink estimated that I spent 75% of my money in the bonus categories. In reality, I spend the vast majority of my money on purchases that would earn me only 1% cash back. Pham says they make that calculation based on a lot of research, and ultimately the company hopes to allow users to be more specific about their spending habits.

If you want more information about credit cards, there are a couple places to turn. If you're looking for business cards, check out this story we wrote about two years ago, about the six best credit cards for small businesses. We'll be updating it in a couple months. And for personal cards, check out Consumer Reports list of the best cash back credit cards. It's a bit outdated, but it's a good place to start.

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