I picked up the Delta Amex with a good sign up bonus and wanted to know how easily I can spend my new miles. I tried making a test award booking (all the steps to book, but cancel on the checkout page to see miles and fees) and after a few searches with NO low level awards, I found a city and date combination. Except when selecting the return flight, I saw the error message below instead. Thanks Delta, I wasn't going to spend my miles, but you made sure of that.
Delta.com Error Message
I do have more respect for United.com's award booking tool, it looks even better now.