I stayed at the Springhill Suites for almost a week. I found the hotel to be extremely clean, the room was spacious and comfortable. I was horrified to learn upon check in that 3 school groups would be arriving that night. However, the soundproofing is excellent and I only heard them when they went to their rooms. Also, the hotel seems to have a good system for dealing with the groups so they don't take over the entire place.
I didn't eat the free breakfast, but it looked great. The garage parking was nice, too.
The hotel is rather far from downtown DC, if that's why you're visiting. The hotel does offer a shuttle to the Metro, but it's still not a quick trip.
The rates on the weekend are great, but during the week it's quite expensive, but not out of line with other hotels in the area.
My one complaint would be the staff. They just didn't seem very experienced or they just didn't care. However, it wasn't enough of an issue not to stay again.