The apartments is really as described - it's cozy and clean, located in nice place from where it's easy and quick to reach almost any location by tram - doesn't matter if it's some business facility like Amsterdam RAI or just a historical center.
Apartment has all that you need for comfort staying and Hellen is very welcome and kind, it's sad that we have met only twice during our staying (after arriving and before departing) due to busy schedule - I'm pretty sure that she can tell a lot about Amsterdam and its history.
I definitely can recommend this apartment as very nice and convenient place to stay at Amsterdam.