We stayed in the studio apartment a couple of weeks ago, during the recent heatwave, and absolutely loved it. It had everything we needed - a great location, very comfortable, and the very nice touches of toiletries, tea and coffee being provided, which we didn't expect.
I can't fault the owners; they could not have been more helpful. Great recommendations for places to eat nearby. Yes, the stairs up to the apartment are very narrow and steep, but it's Amsterdam, and it all adds to the charm!
I would certainly stay here again.