We really had a great stay in Amsterdam with Nima's room. The kitchen and the bathroom is quite big and for sleeping the bedroom has enough space.
Nima was the best host we've ever had. He always answered in a minimum of time! The transport to Amsterdam Centraal Station is rly good. Like the others said, just walk 10min and you can use the free ferry which ships you directly in the centrum.
All in all we would always travel to Amsterdam again whilst living in Nima's room!