The Citibank one holds your money until you cross thresholds ($10,000 spending, I think). It also has a low annual cap ($300 in rebates, I think). If you are using it as your primary card, you might get to September and find yourself looking for another card. I have this card for the purposes of 0% teaser money, but I don't use it for purchases.

Several of the Amex ones have tiers and fine print related to whether or not you carry a balance. That might be OK if you do a ton of spending and can get into the highest tier quickly. I don't know how long Amex invests your rebate before they actually give it to you.

Chase seems to have a good rebate product called Perfectcard. 1% rebate on everything, automatically credited to your next statement. 3% rebates at any gas station. No fee as long as you are using the card. (They apply a fee only if you keep it open and dormant.) I don't know about a cap, and I say "seems to" because I'm always wary of fine print on these cards.