Host: Martin is a very nice host and polite. He answers the question very fast. During some problem happen, he really tries hard to help us even he went aboard.
Apartment: Nice location, very near supermarket+Tram+nice place+RAI conference center. Full of facilities.
Just be noted that (it is not the disadvantage of this apartment. it is a very small point compared to other extremely good things, this apartment is located on 4 fl. with no elevator (normal in Amsterdam). So the preparation of a lot of small luggage might be better than one big luggage.
Again, this apartment is very nice so please feel relax to book it and do not worry about a small thing such as unavailable elevator we mentioned above.