We didn't see Katharine much but when we did she was pleasant. It's clear that having guests in this apartment is a regular thing and it does feel a bit business-like rather than staying in someone's home, someone else was actually arriving one hour after we 'checked out' of the room so it was quite a fast turn around to get the next customer in. The room is quite small and having a suitcase doesn't leave much floor space. One person has to sleep against the window/air conditioner unit which is fine but not great. The room is very tidy and minimally furnished in a tasteful way. Katharine provided bottled water and towels which was a nice touch. There's also wifi which works very well.
It's in a relatively good location for getting the subway to see all the sights of New York however, it should be noted that to get to/from JFK airport it's $55 in a taxi. There's also no lift in the apartment, so if you have big luggage you need to take it up 4 flights of very narrow stairs. Neither of these are huge problems it's maybe just good to know before you arrive.