This place is an absolute winner. The apartment is more spacious in reality than it seems on the photographs - it is very cleverly designed and arranged. It is stylish and modern, and very light, which I loved - and of course, one can darken it properly for a good night's sleep. The bed is very comfortable, all the amenities are great. I especially appreciated being able to wash my clothes, since I had a somewhat longer stay.
As for location, you cannot do any better. It is central enough to be close to everything you need, and just far enough out of the centre of town so that the hustle and bustle doesn't keep you up at night. It faces a lovely, quiet little square, with wonderful restaurants, so one doesn't even have to walk more than 50 paces to find excellent food - and if you want to venture a few hundred paces further, you are in Chinatown, with all its restaurants, and The Hague's central shopping district. It is close to public transport, which makes it very easy to get around.
Arthur is a fantastic host. He is very friendly and helpful, and made checking in-and-out a breeze - and he even got up early to help me with my luggage when I had to catch an early flight. I will certainly return, and I will recommend this apartment to anyone who asks.