This was our second stay at the Hilton Garden Inn, and it remains a nice, comfortable property in a very convenient location in DC. Checkin was fast and efficient and service by all the staff was friendly. As others have mentioned, rooms are standard size and comfortable and have all the amenities you would expect from a Garden Inn.
On the negative side, yes there is some street noise that comes through these windows, even if you are on a high floor. It's a busy road with lots of traffic and activity. Also, the breakfast buffet, while nice, does not have the standard layout for a Hilton Garden Inn. The flow simply does not work, and on a busy weekend there was a very long line for the cook to order station. Compound this with a poor layout of items, and it just breaks down as people struggle to find what they need. They might do better to standardize this dining room like the other hilton garden inn's. The waitstaff at the breakfast buffet was great, very friendly and attentive.
Overall, I would recommend this hotel and would stay again.