I have stayed at the Marriott in Bethesda, MD on two separate occasions: two weeks in November of 2011 and one week in July of 2013. On each occasion I found the front desk staff very friendly and helpful. First, I'm a sucker for a good breakfast and theirs is simply spectacular, especially when compared to the continental or other types of included breakfasts that you get with other hotels. You always get some variety and it's not just some toast and cereal like it is some places, but a wide array of choices from waffles to fresh fruit, scrambled eggs and home fries to parfaits. Beyond that they offer light dinner 3 days of the week (included with most room stays). All of their facilities are kept sparkling clean including the gym and laundry room. I didn't have much time to use the pool, but even that was clean and comfortable, though not the size you'd want to try to do laps in. My room during each visit was clean and comfortable. The beds are more comfortable than the one I have at home.
With such friend and informative staff, great facilities, clean and comfortable rooms, and great food there's no way to go wrong here.