Not worth it ...
We stayed at Holliday Inn Capitol Hotel on a 3 days trip in WA DC … 
I’m not going to say it was bad but it was definitely not a good experience.
First of all the room was extremely small, with 2 double beds instead of 2 queen beds and very little space around them. We booked the room online and we could book it for 3 adults and 2 kids, so I expected to have at least 2 queen beds … 
The bathroom had a decent size but looked outdated and the hairdryer had hair on it so we could not use it. 
The big disappointment came from the other hidden fees we were asked to pay after the check in – when we booked the room we picked the option with breakfast included to find out at the hotel that breakfast was just for 2 adults …they wanted to charge us for the thisrd adult. After showing my disappointment they finally agreed that all 5 of us will have breakfast included. Then, in the morning we found out that the kids had free breakfast JUST if they order from the menu and not from the open bar … of course the menu did not have so many options as the open bar. So 3 adults ate from the open bar and the kids from the menu. Also, they say kids eat for free with a paying adult lunch or dinner but the dinner prices were very high for not sophisticated food so we did not take the chance.
The parking fee, at the hotel was $30/day – a fee I never read about on-line. 
The hotel has wireless internet connection, but it is so bad, I mean so slow that we got tired to use it …so do not count on that, it’s like does not exist.
The only big plus of this hotel is the location – right behind Air Space Museum and all the money you pay is for this. But be aware that there are not restaurants in the area, so you will have to drive or to pay a taxi to eat dinner.
I would no go back – the subway runs very good in WA, I would rather book a hotel farther away, but close to a subway station.