We booked Ann's apartment for 3 nights in late June 2012 (a couple of weekend travelers).
Upside:
The location is nice, very close to Vondelpark and the house is located just on the canal.
Downsides:
The construction next to the building. The terrace was covered with dirt from the works in the neighborhood.
Not fresh bed linings. It seems they were not changed from the previous guests or just were not washed properly.
Dusty pillows. My wife got her eyes irritated. The pillows could definitely have some cleaning.
The cleanliness of the kitchen. I come to Amsterdam often and I've been to many apartments. That was the first time when I didn't want to bring food home and cook.
The floors were quite dirty. I'm not sure if the apartment had any cleaning recently. I wonder why there is a cleaning fee applied.
A lot of stuff in every corner. Not much free space at all.

Neither Ann nor her sister were available for discussion and couldn't come to the apartment when we expressed our dissatisfaction.
We stayed in the apartment for one night and have moved to another one, having made a last-minuted booking.
We were ready to pay for one night we stayed and asked Ann to return the payment made for the rest two days. Unfortunately, Ann refused.

All in all, the apartment is ok if you like Vondelpark and do not care about the tidiness and cleanliness of the place. If you do - there are a lot of alternatives around.