Nik's place has the best location. Less than 10 minutes walking from Amsterdam Centraal station and next to some of the most beautiful canals in Amsterdam. It's in a less busy and noisy neighborhood so you can expect a perfectly quiet night. The apartment is in the ground floor with a big window overlooking the street. The shower room has been recently renovated and it was great.
Nik is a great host, we told him it was a bit cold and he did all he could in order to improve it and make our stay great. On our last day, he was VERY kind and kept our luggage and waited for us to come back.
I definitely recommend staying at Nik's place.