My boyfriend and I stayed at the Sheraton in Silver Spring, MD for our week vacation in DC. It was cheaper than staying in the District, but close enough to the Metro to enable us to get into town every day.
Our experience with the hotel was pretty standard. It's nice that there is a Starbucks in the lobby, and the restaurant and lounge looked nice, but we didn't use them.
It rained many of the days we were in town and, unfortunately, the hotel did not offer umbrellas to borrow for the day. They did, however, offer a free shuttle anywhere within 3 miles - so we took the shuttle to the Metro a couple days. It's first-come/first-served, so sometimes the shuttle required a bit of a wait, but I think the longest we waited was about 10-15 minutes. They won't let you call from your room to request it; you have to be in the lobby waiting.
We ordered room service one night. It was fast, correct, and tasty. We even asked for extra ketchup and they ran down and brought us back 4 little ketchup bottles!
The bed was pretty hard for me. I woke up every morning with back pain. My boyfriend slept just fine, and he usually has problems. And the pillows are nothing but air. I asked for a firmer pillow and they didn't have any.
If you're looking for a tasty yet simple breakfast/lunch/dinner, the Tastee Diner on Cameron is right around the corner and is great. Also, the deli just across the street was pretty good for quick sandwiches.