There do appear to be some restrictions:
"Purchases not eligible to receive the 5% rebate include, but are not limited to, purchases made at warehouse clubs, discount stores, department stores and convenience stores. Online and catalog purchases are not eligible to receive the 5% rebate unless the merchants appropriately identify the transactions. We do not determine whether merchants appropriately identify the transactions, but we do reserve the right to determine which purchases qualify for the 5% rebate."
"You may accumulate a maximum of 300 Dividend Dollars in any calendar year (eligible transactions appearing on your January - December billing statements) payable in checks of $50 or more only upon your request. Dividend Dollars earned on purchases through the Citi Dividend Merchant Network are not subject to the $300 calendar year maximum accumulation."
That works out to be about $25 in rebates per month or about $00 (at 5%) or $2,500 (at 1%) in purchases. I use a Hess branded Visa that gives me 5% on gas purchases and 1% on *all* other purchases. I always exceed $25 in rebates per month.
I'm not arguing against the card, just pointing out that, as with all these "rebate" cards, you need to look at your purchasing trends and the limits on the cards.