Rewards Checking has been common knowledge for a long time. The account terms have been getting progressively worse over the past couple years. They typically require 10-12 debit card transactions per month, and there's always a maximum balance limit (usually $5,000 - $25,000) above which you will only get a nominal interest rate. So you really shouldn't look at the percentage rate, you should look at what the actual dollar payout would be and decide if it's worth jumping through the hoops. For example, if you're essentially capped at $30/month, you have to ask yourself if it's worth the hassle of meeting the debit card requirement (and giving up on credit card rewards for those transactions).
The terms change very frequently on these accounts. For example, I opened one and it went through the following transitions over a year:
1. 5% on $25,000; 1% above $25,000.
2. 4% on $25,000; 1% above $25,000.
3. 4% on $15,000; 1% above $15,000.
4. 3% on $15,000; 0.25% above $15,000.
Change 4 was the worst, as I now have to try to keep the account AT $15,000 but not much over. Given that money above $15,000 would now be better off at ING or Ally, the account is essentially capped at $37.50 interest per month, and I'm also losing about $4.50 in credit card rewards on the debit card transactions, so that effectively brings it down to $33/month. I'm seriously considering dropping it.
Keep in mind that you typically have inferior fraud protection with a debit card compared to a credit card.
And yes, this is a Kasasa account, but there are a ton of Rewards Checking providers and they all work basically the same way. Expect the terms to change for the worse every few months.