I was in Amsterdam for less than 24 hours after a quick trip to Nijmegen. Ned and Keiko's had close access to trams and trains to get around town and quick access to the airport. The neighborhood they're in is quaint, with lots of shops/restaurants, but still relatively quiet. The room is on the top floor of a building with steep stairs, something to be aware of if you have a lot of luggage.
Ned and Keiko had great instructions for check-in/checkout and were always quick to respond. If I return to Amsterdam, I would absolutely stay with them again!