Tried it for the first time this morning in EWR, with no problems, but not done it at DCA.

Best bet when you are trying it for the first time is the carry a paper copy in your bag as backup. Also, remember to alert the WTMD operator who will take a look at your PDA, then have you put it through the x-ray.

Other than not longer having a piece of paper to store/throw away when I'm done, I'm not really sure if the new technology benefits me much.