I spent one weekend in Amsterdam with 4 friends and stayed at Roos apartment. The apartment is located outside the city center, but is very well connected and takes around 10-15 min by tram (the stop is 100 m from the apartment) and 25-30 min walking. Roos was very kind, and provided all kind of suggestions about the city, restaurants and pubs. The house is really nice, with a large and bright hall, and a nice balcony. I warmly suggest this apartment for your next trips in Amsterdam!