Stayed here recently and would agree with other posters that its not bad, not good, just ok.
No issues with the room but Breakfast had issues, the two servers on duty seemed to be overwhelmed.
For me, was not offered the option of ordering from the menu, which I had intended to do. Also had to remind server that I had made beverage selections. Given everything else was self-serve buffet, that was not great. I debated asking to see the menu, but then noticed the lady at the next table waving down a server to ask where her breakfast was (her colleague was already 50% done with her food). I was on a tight timeline, so decided to cut my losses and stick to the buffet. Buffet was standard US Hyatt Regency fare in terms of quality and variety. The menu options did look good for those lucky enough to get them

I would probably stay again, especially now that I know I would need to be more proactive in the breakfast room so could take action to mitigate their shortcomings, eg. get to breakfast earlier, request the menu, be more pro-active if it appears they are forgetting something....

This was also my first time at IAD, what a strange airport.