My girlfriend and I very much enjoyed this apartment and the neighborhood. It was amazing to stay in such a historic building. The place was very comfortable, very clean, and nicely decorated. The kitchen was well appointed and everything - showers, plumbing, appliances, etc - worked perfectly. It was quiet and felt safe. We liked the view, the breeze, and the canals below. I liked the loft area and wish I'd had an afternoon off to just lay up there and read.
The stairs are, as noted in the other reviews, comically steep. But unless you've got some significant mobility problems, you'll probably end up just getting some funny travel stories out of them, proof of the historic authenticity of the building.
We were able to walk to all the things that we wanted to visit: The Rijksmuseum, the Anne Frank House, the Stedelijk Museum, etc. A lot of just wandering around and enjoying the sights and cafes around the canals. If you have time, walk over and visit the Amsterdam Public Library if you're a fan of architecture and/or books - it's very close.
The proximity to Centraal Station (basically across the street) is supremely convenient for getting in and out. There's tons of cafes around and a nice market a block away to stock the kitchen.
Marcus and Monique were great hosts. Very accommodating getting checked in after a long night of travel, and very helpful with information about getting around Amsterdam and with information about taking the trains to our next stop, Brussels. Very nice folks all around and we enjoyed our interactions with them.
Great trip start to finish and we hope to come back to Amsterdam soon. If this place isn't booked up we'll stay here again! Thanks Marcus & Monique.