Staying with Jeanine and Sergio was most enjoyable. Arriving there was very easy, everything was ready, the room exactly as described on their page, the bed comfortable (I have terrible shoulder problems, so I really appreciated the bed being good), the kitchen and bathroom impeccable. Jeanine and Sergio were both lovely people and very, very helpful, so much more than I would have expected :-) I had nice chats with them and the other people staying there, too. Everybody was very respectful of the privacy of others, never had any trouble with bathroom turns or such. The atmosphere was relaxed and pleasant.
When it comes to the neighbourhood, it was a lively and safe one, many nice places for eating out and some grocery stores just around the corner. I personally like Harlem best out of all NYC areas, it is interesting and groovy, and I never experienced anything unpleasant there. This was my 3rd visit in the city, and based on previous experiences of Harlem I especially wanted to stay there :-) 125th street is a fun street to hang around and do some shopping. Central Park is a 10 walk from the apartment, and a few blocks away is the subway that will take you downtown in no time.
I would definitely stay at Jeanine and Sergio's again if I had the chance to revisit New York any time soon!