We have switched over to Capital One for all of our rewards. I like that we are not locked into a single or small group of airlines as you often are with miles. I can search around and get the best deal, pay for it with my Capital One card (earning additional points in the process), and then use my points to reimburse my travel expenses. I still get frequent flyer miles and credit from the airline on tickets I purchased with the Capital One points. There are no blackout dates and as far as the airline is concerned, I simply paid for the ticket myself. Also, the points can be used for any other travel related expenses as well. Finally, if you don't use the points for travel you can use them for other purchases, but at a lower reimbursement rate.

edit: Forgot to mention that Capital One also doesn't charge foreign transaction fees