Firstly, about the stay itself:
Greg's place is located about 20 mins away from the city, and is situated about a few minutes away from the tram station that will take you directly to the heart of the city. This provides the best of both worlds in my opinion -- it provides easy access to do all that you want in the city, and you can come back to a quiet environment without the hustle-and-bustle of city life. The apartment itself is clean, has all the amenities you can ask for (kitchen, laundry, private bathroom), and the room even has a balcony where you can come back and relax.
About the host:
Greg is a wonderful host and that's an understatement. He is promptly responsive to all questions. There was a mishap during my trip where my luggage was delayed, and I had the airlines ship it out to Greg's apartment. Unfortunately, the luggage only arrived in Amsterdam after I had already left, but Greg went through the trouble of picking it up once delivered and shipped it out to New York the day after. I cannot recommend his place enough for anyone hoping to enjoy Amsterdam.