Excellent apartment in a great location - within walking distance to many major sights in Amsterdam. The apartment was very clean and had everything you'd need (including a washer / dryer). The check-in process was very smooth and straightforward - Martine had someone meet us on arrival to show us the apartment, its amenities, and how to check-out when leaving. We were even provided with a bottle of champagne on arrival.
One thing to note is that the staircase to get to the apartment is very steep and a little bit of a climb to the 4th floor - while it didn't bother us, I thought it should be something to note. Once in the apartment, however, the views were very nice and the terrace seemed like it would be nice to use in the summer (unfortunately we didn't get a chance to use it). There were also restaurants nearby and a tram stop right in front of the apartment which was convenient.
Throughout the whole process Martine was very communicative and answered any and all questions we had. I highly recommend staying in this apartment if you find yourself traveling to Amsterdam.